An ice cream laboratory guide

The manufacture of ice cream is based on certain scientific principles. It is the purpose of this laboratory manual to help the student to better understand the application of these principles. This manual, which is the result of several years’ experience in teaching, is not intended as a textbook, but as a brief and concise outline of laboratory exercises. It will also serve as a suitable place for the student to record observations. The exercises have been prepared, so that each instructor may make selections and combinations suitable for the equipment and the needs of his course.

Because this is comparatively a new subject and the ideas regarding ice cream production and manufacture are constantly changing, the authors recognize that this manual will need frequent revisions. An effort will be made to keep it thoroughly up to date.

The exercises in this manual may be selected or easily modified, so that they will be suitable for any laboratory equipment. For example, the receipts have been prepared with the expectation that a 10-gallon freezer would be used; if a smaller freezer is used, the receipts may be reduced proportionally.

Much better instruction can be given if the equipment includes an artificial refrigerating plant for freezing and hardening the ice cream. If the equipment does not include an artificial refrigerating plant, a tub and can freezer, using an ice and salt mixture for freezing, and a wooden box for packing and hardening the ice cream, in ice and salt, may be used. The hardening box should be made of 2 inch matched lumber so that it will not leak. The size of the box will be determined by the amount of ice cream manufactured. It should be built in compartments which will hold six five gallon cans. This will require a box 26 inches wide by 32 inches deep by 36 inches long, outside measurement, with a hinged cover for each compartment.

If much ice cream is to be made an ice cream mixer is a necessity, but if a small amount is made each batch may be mixed in a 40 quart milk can. A homogenizer and emulsor may be included in the equipment.

With whatever type of freezer is used, there should be one or two small [Pg 4] hand freezers, to freeze small batches and to try new receipts. An ice crusher should be included for crushing ice.

The equipment should include the necessary small utensils, such as pails, dippers, ladles, spoons, thermometers, scales, measures, pack cans, etc.

There should be a suitable sink connected with hot and cold water and steam, for washing and scalding the utensils. A suitable rack should be provided for drying and holding the utensils and pack cans. Because of the salt used, care must be exercised, as it is liable to get on the utensils and cause them to rust.

All belts and gears on machines should be protected, so that persons cannot be caught and injured in them. [Pg 5]

INSPECTION AND STUDY OF
ICE CREAM MACHINERY

STANDARDIZATION

One of the main requirements for a successful ice cream business is uniformity of quality. In order to obtain this, it is necessary to have cream each time containing the same percentage of fat. As it is impossible to always get cream of a uniform fat content, the cream must be standardized. That is, the percentage of fat must be either increased or decreased to the desired amount. It is the usual practice to have richer cream than is to be used and reduce it by the addition of less rich cream, whole milk, or skim milk. If the cream was lower in percentage of fat than was desired, it could be standardized only by the addition of richer cream.

Prof. R. A. Pearson has devised a very simple method, known as the rectangular method of standardization. This method is as follows: draw a rectangle and place in the center the percentage of fat desired. At the left hand corners place the percentages of fat in the materials to be mixed. It is customary to place the larger figure at the top, thus:

Then subtract diagonally, placing the remainders at the right hand [Pg 9] corners, as shown above. These show the proportions by weight in which the materials must be mixed to give the desired percentage of fat.

How many pounds each of 30% cream and 4% milk are necessary to make 260 lbs. of 20% cream?

To be sure no mistakes are made in figuring, it is best to prove all standardizations. The proof is simple.

In the above problem a definite amount of the mixture was required. There is another class of standardization problems in which the amount [Pg 10] of one of the materials is given, to find the quantity of the other required to standardize it:

How much 4% milk must be mixed with 420 lbs. of 40% cream to make a mixture testing 25% fat?

This shows that 15 lbs. of 4% milk will standardize 21 lbs. of 40% cream to a cream tasting 25% fat. But there are 420 lbs. of 40% cream to standardize. By simple proportion,

Test both by the Babcock method and report the result to the instructor, who will assign a definite percentage of fat for the standardized mixture.

After standardizing, test a sample of the standardized mixture by the Babcock method to test the accuracy of your work.

Ice cream cannot be tested for fat, by the Babcock test, as milk, because the acid chars the sugar, which interferes with the reading. Various methods of testing ice cream, so as to overcome this disadvantage have been devised. A few of the simpler ones follow.

Test a sample of ice cream by each of the following methods and report results on the opposite page.

Method of Prof. H. E. Ross: Mix equal parts by weight of melted ice cream and water. Weigh into a 9 gram 50% cream bottle 9 grams of the mixture. Add 17.5 cc. of glacial acetic acid. Shake for two to three minutes. Next add 15 cc. of sulphuric acid such as is used for the Babcock test. Shake for one minute and proceed as in the ordinary Babcock test. Multiply the reading by two.

Method of J. P. Dawson: Weigh 18 grams of melted ice cream at a temperature of 70 degrees F. into a 30%, 9 inch cream test bottle. Add 8 cc. of glacial acetic acid, agitate gently for 2 minutes and add 10 cc. of Babcock sulphuric acid. Shake and centrifuge in the usual manner.

Note: There appears to be no reason why one half the quantities of ice cream and acids may not be used in a 6 inch 9 gram 50% cream bottle.

Method often used by the authors: Weigh 9 grams of melted ice cream into a 6 inch 50%, 9 gram cream bottle and add about 9 cc. of water. Add three quarters of an acid measure of glacial acetic acid and mix thoroughly. Next add two thirds of an acid measure of Babcock sulphuric acid. Shake till well mixed and centrifuge in the usual manner. [Pg 15]

EFFECT OF THE SALT AND
ICE MIXTURE ON TEMPERATURE

Make a brine one part salt to ten parts of water by weight. With part of this fill the can of a hand freezer two thirds full just as though it were an ice cream mix which you were going to freeze. Record the temperature of this brine.

Trial 1. Using a mixture of one pound of salt to 10 lbs. of crushed ice, try freezing the brine in the freezer can. Turn 10 minutes, keeping the freezer can well covered with the ice and salt mixture. Open and record the temperature of the brine in the can.

Trial 2. Empty the freezer can and tub and refill the can with more of the brine used in Trial 1. Be sure to have it the same temperature. Using a salt and ice mixture of the same proportions, pack the tub again and in addition add enough cold water so that it starts to run from the overflow hole in the tub. Turn the freezer 10 minutes, recording the temperature of the brine flowing from the overflow hole every 2 minutes. Be sure to keep the ice-salt-water mixture in the tub well mixed by punching with a stick such as a sawed-off broom handle. Again record the temperature of the brine in the can. Why does it differ from what it was in Trial 1?

Trial 3. Repeat Trial 2, except use a mixture of salt and ice one to six instead of one to 10. Record results.

Trial 4. Repeat Trial 3 but do not mix the ice, salt, and water [Pg 17] in the tub. Explain the difference in the results obtained in Trials 3 and 4.

CLASSIFICATION OF ICE CREAM

In the absence of the adoption of any uniform standard classification of ice cream, the following classification in use by the authors is given. It is simple, yet comprehensive, and is arranged according to fundamental differences in composition. This seems to be the most logical basis for classifying ice cream and is very satisfactory from a laboratory standpoint. Exercises and representative formulas will be given for each of these classes.

I. Plain or uncooked ice cream, often known as Philadelphia ice cream, is made from cream, sugar, and flavoring, with or without condensed milk or some stabilizer. It may be subdivided as follows:

II. Cooked ice cream, often known as French or Neapolitan ice cream, is made from cream, sugar, flavoring, and eggs. As custards they sometimes contain flour or cornstarch. The following subdivisions are recognized: [Pg 19]

III. Sherbets and Ices are made from water or milk, sugar, often egg albumen and a stabilizer, and flavored with fruit juices or other natural flavoring. The most prominent classes are the following:

1. Ices—Made from water, sugar and some natural flavoring without eggs or a stabilizer. This may include granites and frappés. Granites are frozen with little agitation, while frappés are only semi-frozen to a slushy consistency.

2. Water Sherbets—are made the same as ices with the addition of egg whites and sometimes a stabilizer. If the whole egg is used, they are sometimes called souffles.

3. Punches—are ices or water sherbets flavored with liquors or highly flavored with fruit juices and spices.

4. Milk Sherbets—Made from skimmed or whole milk, sugar, and egg whites, with or without a stabilizer and flavored with some natural flavoring.

5. Lacto—Made from skimmed or whole sour milk instead of sweet milk but in other respects they resemble milk sherbets.

IV. Mousse is a rich cream, sweetened and whipped to a stiff froth, flavored and frozen in moulds or cans.

In the laboratories at the New York state agricultural college 20% cream is used in making all plain or uncooked ice creams. Therefore in [Pg 20] the following exercises and formulas a 20% cream is used as a base in most cases. This, however, may be reduced to 18% or 16% if it is thought desirable.

It must be remembered that the formulas given are for laboratory use and are not especially recommended as ideal formulas for commercial use. Many of them have given good results in commercial plants but there are so many variations and combinations possible that no single formula or group of formulas can be given as ideal for all commercial plants.

If the use of condensed milk is desired eight pounds of whole condensed milk may be substituted for the same amount of cream with excellent results in any of the formulas given for plain ice cream. Most commercial plants use condensed milk to give the ice cream more body and better standing quality.

THE USE OF STABILIZERS

A stabilizer of some kind is generally admitted to be necessary in commercial ice cream. The three most commonly used are gelatin, ice cream powders and gum tragacanth.

Gelatin may be prepared in any of the three following ways, using either milk or water for dissolving it. However, if milk is used, one of the first two methods should be used, so as to avoid any cooked flavor from boiled milk.

1. Using one pint to one quart of water or milk to each two ounces of gelatin, soak the gelatin in the cold liquid for fifteen to thirty minutes. Then heat the mixture up to a temperature of 160 degrees to 170 degrees F. and add to the cream with rapid agitation.

2. The same as number one, except heat the mixture only to a temperature of 125 degrees to 130 degrees F. for a sufficient time to thoroughly dissolve all of the gelatin.

3. Heat the necessary amount of water to boiling, dump the gelatin into it and stir till dissolved. Then add to the cream with rapid stirring.

Gum tragacanth stock is made in the following manner. Place the dry gum in cold water, using one ounce of gum to four pounds of water. Heat slowly and uniformly over a low flame or better in a double boiler to a temperature of about 110 degrees F. Hold at this temperature for several hours or until the dry gum has absorbed all the water it will hold. It does not go into true solution in water but will absorb about [Pg 22] fifty times its own weight of the water. Strain through a coarse strainer and cool. It is then ready for immediate use. Sometimes enough is made at one time to last for several days, in which case it is best to add sufficient sugar to keep it from spoiling. [Pg 23]

Freeze ice creams after the following formulas, which may be reduced to suit the capacity of the freezer used. Eight pounds of whole condensed milk may be substituted for eight pounds of the cream if desired. Fill out the record blank on opposite page.

METHODS OF MEASURING SWELL

Freeze one or more batches of plain ice cream as assigned and measure the per cent. of swell in each of the following ways. Record results on the opposite page.

1. Measure the gallons of mix used. Then measure in packing cans the gallons of ice cream obtained and calculate the per cent. of swell.

2. Weigh one gallon of the mix. Weigh the first gallon and the last gallon of ice cream removed from the freezer and calculate the per cent. of swell in each case.

3. Take two samples, preferably from different packing cans of ice cream from the same freezer, and determine the per cent. of swell by the method given in Bulletin 241 of the Wisconsin Station as follows: Take a 50 cc. sample of ice cream with the sampler furnished you and transfer to a 300 cc. beaker, using exactly 200 cc. of hot water to melt it. Then transfer all of this to a 250 cc. Florence flask and add 1 or 2 cc. of ether (measured) to reduce the foam. Next add enough water measured from a burette to fill the flask to the mark. The ether and water required represent the swell. Calculate the per cent. in each case.

Which method do you consider the most accurate for commercial use and why? For experimental use and why? Give special advantages of each test. [Pg 27]

HARDENING ICE CREAM

Ice cream may be of the highest quality when removed from the freezer and yet be ruined before it becomes hard enough to ship unless the hardening is properly accomplished. The two principal methods in use are the salt and ice method and the artificially cooled dry hardening room where the cans of ice cream are simply set in a very cold room and hardened by still or circulating cold air. The temperature of such a room should be maintained at near zero F. With either method the hardening process should not require more than twelve hours. The packing cans should always be cold before they are filled with ice cream, so as to prevent melting in the bottom.

Directions for hardening in salt and ice. Either ordinary packing tubs or a large box may be used for this purpose. If tubs are used, simply pack well with salt and ice mixed in the proportion of one to eight. It is necessary to repack these tubs two or three times a day in order to keep the ice cream hard. When several cans of ice cream are to be hardened at a time a better method, more economical in labor and material, is to pack the empty cans up to the covers in a large box, using salt and ice, one to eight. The soft ice cream is poured into these partly packed cans and when full they are completely covered with the ice and salt mixture. With such a box it is not necessary to repack oftener than twice a day. [Pg 29]

Freeze fruit ice creams after the following formula, using such of the flavors as are assigned. Fill out record blank on opposite page.

Flavors: Pineapple, raspberry, peach, cherry, strawberry. Either fresh or canned fruit may be used.

If a perpendicular freezer is used, the fruit should not be added until the ice cream begins to thicken, which will prevent the fruit settling to the bottom of the freezer.

Freeze nut ice creams as assigned, using the formula given below. Fill out the record blank on opposite page.

It is better if all of these, except the walnuts, are blanched before using by scalding with boiling water and removing the skins.

Prepare the nuts by running them through a meat chopper and add to the ice cream after it freezes enough to begin to thicken.

Freeze bisque ice cream after the base formula given below, using such of the following flavors as are assigned. Fill out the record blank on opposite page.

Any bread product used should be dried sufficiently so that it may be easily crushed into fine crumbs. If perpendicular freezer is used, do not add the crumbs until the ice cream freezes enough to begin to thicken. [Pg 35]

Freeze the following plain ice creams as assigned. Freeze in the order given. Fill out record blank on the opposite page and make bricks and molds of the ice cream as directed below.

Fill the outside of a few center mold bricks with vanilla ice cream. Harden in a salt and ice mixture one part salt to two parts of ice. [Pg 38] When hard withdraw the center mold and fill with the strawberry or chocolate ice cream. Again pack in salt and ice to harden.

Fill a few fancy individual molds and pack in the salt and ice mixture till hard.

Each student should make a 3 layer tri-colored brick. First prepare the molds, attach your name and pack in salt and ice to become thoroughly cold. As the vanilla ice cream is drawn from the freezer fill each mold one third full and pack in the salt and ice mixture, so that it will be hardened by the time the strawberry ice cream is ready to be drawn off. Then fill another one third with the strawberry. Finish filling with the chocolate, being sure to have the brick so full of soft cream that no brine can enter under the lid. Care should be taken each time to have the bricks set level in the salt and ice. [Pg 39]

Freeze custard ice creams after the following receipts as assigned and fill out report blank on opposite page. Quantities given are for hand freezers.

Put the milk over the fire in a farina or double water boiler. Moisten the cornstarch with a little cold milk so that it can be added to milk without lumping. When the milk is hot, add the cornstarch and stir until it begins to thicken. Beat the eggs and sugar together until light and then add them to the hot milk. Cook a few minutes, take from fire, flavor and cool and freeze same as ice cream.

Other flavors as coffee or chocolate may be made by substituting these flavors for the vanilla.

Cook the tapioca in two quarts of milk for 10 minutes, then add the rest of the milk, the sugar and salt. Cook ten minutes longer. Remove from fire and add the egg yolks well beaten. Then add the extract, cool, and freeze. When nearly done, add the cream previously beaten to stiff froth and finish freezing. [Pg 43]

Freeze the following receipts as assigned and fill out report blank on opposite page.

Beat the egg yolks till smooth, add the sugar, and beat again till it is dissolved. Beat the whites to a stiff froth and stir into the yolks and sugar. Mix all with the cream and cook in a double boiler to a temperature of 180 degrees F. for 15 minutes. Cool to 40 degrees F., add vanilla and freeze.

Beat whole eggs together, add to the mix and freeze, or the whites may be beaten separately if desired and added after the mix is partly frozen.

[Pg 46] Beat the egg yolks till smooth, add the sugar and beat again. Then add to the cream and cook in double boiler to 180 degrees F. for 15 minutes. Cool, add the balance of the mix and freeze. [Pg 47]

Freeze the following puddings as assigned and fill out report blank on opposite page.

Use the eggs as directed under receipt number one. Chop the fruits and nuts fine. [Pg 50]

Freeze the following water ices as assigned and fill out record blank on opposite page.

Freeze the following sherbets as assigned and fill out record blank on opposite page.

Freeze milk sherbets after the following base formula, using such of the flavorings as are assigned. Fill out the record blank on the opposite page.

Flavors: Orange, grape, cherry, pineapple, and strawberry. If lemon is desired, use only two quarts of lemon juice with a quart of orange juice.

Freeze the following formulas as assigned and fill out the record blank on opposite page:

Mix in the order given in the formula. Other flavors may be substituted for the grape juice. [Pg 59]

Dissolve the sugar in the fruit juice, then stir in the gelatin dissolved in a very little water. Chill this mixture but not enough to form a jelly. Whip the cold cream till stiff and then fold in the gelatin-sugar-fruit mixture.

Pack into molds or cans and harden in a salt and ice mixture one to two. Other flavors may be substituted.

Dissolve the gelatin and stir into the cream. Whip till stiff, then fold in the sugar and vanilla and pack in cans, hardening in salt and ice mixed one to two.

STANDARDIZE MIX TO A GIVEN
PERCENTAGE OF FAT

The following materials will be furnished: cream, milk, sugar, chocolate, fruit, vanilla and gelatin. From them make up a receipt and freeze a batch of ice cream to contain a given per cent. of fat as assigned.

Test the frozen ice cream for fat and report the result to the instructor at time of testing.

Mark plainly each can of ice cream with the receipt number, your name, and the date.

SCORE CARD FOR ICE CREAM

The comparison of ice creams is accomplished best by reducing their quality to a numerical basis. This is done by use of a score card. Two score cards are suggested as follows:

It may be more advantageous to use the Cornell score card in the Laboratory because immediate results can be obtained, while with the modified Wisconsin score card bacterial counts must be made of the ice cream, so that it would be two to three days before the final score of the ice cream could be obtained.

Discussion of Qualities of Ice Cream

Flavor. The ice cream should have a pronounced flavor which will blend with the flavor of the cream to give a clean, desirable typical flavor.

Body and Texture. The body should be firm and mellow. It should not be tough or rubbery neither soft or mushy. The texture should be smooth and velvety and entirely free from graininess and lumpiness.

Richness. If the ice cream meets the legal requirements, it should be given a perfect score. If it falls below the legal requirement, it should be scored zero. [Pg 65]

Appearance. The ice cream should have an attractive appearance and be of the characteristic uniform color.

Package. The package should be neat and clean and, if for long shipment, some provision should be made to protect the ice on top of the packing tub.

Bacterial count. An ice cream which has a count of 20,000 should be considered perfect. For each increase of 20,000 above this one point should be deducted from the score.

Application of score card. When judging samples of ice cream, it is best to try some of them to obtain some idea of the qualities of the samples to be scored. This is necessary so that the score will not run above 100 and to set a standard. Then with a definite standard in mind, the samples may be carefully scored. The cuts in score should be made in proportion to the quality of the ice cream and the definite standard in mind.

Score and criticize the samples of plain ice cream recording the scores on the opposite page. (For score card see page 64.)

One sample will first be scored by the instructor as an example and guide to the severeness of the cut for different defects. After the students have finished, he will score the remaining samples with them.

Three of the samples are ice cream made in the college laboratory. The others are purchased and represent well known commercial ice creams.

After scoring on all other points make a fat test of each sample. (See page 14.) [Pg 67]

Part I. Freeze ice creams after the following formulas as assigned. Each has a different percentage of fat. Fill out the record blank on opposite page and mark plainly each can of ice cream with the receipt number, your name and the date.

Part II. After hardening or next laboratory period score and criticize the ice cream made in Part I. Fill in the score blank on page 90. [Pg 69]

Part I. Freeze the following mixes as assigned. Fill out record blank on opposite page, and mark each can of ice cream plainly with receipt number, your name and date.

Part II. After hardening or at the next laboratory period score and criticize the ice creams made in Part I. Fill out the score blank on page 91. [Pg 71]

Part I. Freeze the following mixes as assigned. Fill out record blank on opposite page. Mark each can of ice cream you freeze with receipt number, your name and date. Calculate and record the approximate per cent of fat and of milk solids not fat in each mix.

Part II. After hardening or at next laboratory period score the ice creams as made above. Fill out the score blank on page 92. [Pg 73]

With sufficient fresh cream to make four batches of ice cream, divide the cream into four equal parts.

Twenty per cent. cream of nearly uniform quality will be furnished you, of the following ages from the separator: three to four hours, one day, two days, three days, and five days. Freeze a batch of each as assigned, using the following formula, and pay special attention to the swell obtained.

Also test each cream for viscosity by dropping from a pipette on an inclined glass, taking care to have the glass and pipette of even temperature for each trial.

Make enough mix for four 10 gallon batches of ice cream, using the following formula:

Freeze the first batch as a preliminary one. Have the second at a temperature of 40 degrees F., when it enters the freezer, the third at 50 degrees F., and the fourth at 60 degrees F. Warm to these temperatures before placing mix in freezer. Note swell obtained. Explain.

EXERCISE NUMBER XXVII
EFFECT OF THE TIME OF FREEZING ON
THE SWELL AND QUALITY OF ICE CREAM

Make enough mix for four 10 gallon batches of ice cream, using the following formula:

Freeze the first batch as a preliminary one. Regulate either the temperature or quantity of brine so that the second batch will freeze in four minutes, the third in fifteen minutes, and the fourth in thirty minutes.

EXERCISE NUMBER XXVIII
BACTERIAL COUNTS OF ICE CREAM

This exercise is to be performed once during the course by each student as assigned.

Sterile glassware and media will be furnished you. Weigh or measure the samples for dilution as instructed.

Take samples as indicated below in sterile bottles and plate on plain lactose agar. Incubate at 37 degrees C., for 48 hours.

Weigh 5 gram samples of gelatin into 100 cc. of cold water in beakers or jelly glasses. Allow it to soak over night. Then heat slowly, with stirring, to 80 degrees C.

Two or more students should be assigned to this exercise at a time, each having a different sample of gelatin. They should perform the tests together. [Pg 85]

Visit at least one large commercial plant some time during the term and report on the following points.

Each student should hand in one receipt for ice cream. This receipt should be one which has been previously tried, preferably at home.

*** END OF THE PROJECT GUTENBERG EBOOK AN ICE CREAM LABORATORY GUIDE ***

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	PAGE
Preface	1
Discussion of Laboratory Equipment	3
Exercise I
Inspection and Study of Ice Cream Machinery	6
Discussion of Standardization	8
Exercise II
Standardization	12
Exercise III
Testing Ice Cream for Fat	14
Exercise IV
Effect of the Salt and Ice Mixture on Temperature	16
Classification of Ice Cream	18
The Use of Stabilizers	21
Exercise V
Freezing Plain Ice Creams	24
Exercise VI
Methods of Measuring Swell	26
Hardening Ice Cream	28
Exercise VII
Freezing Fruit Ice Cream. Hardening in Salt and Ice	30
Exercise VIII
Freezing Nut Ice Cream	32
Exercise IX
Freezing Bisque Ice Cream	34
Exercise X
Making Bricks and Fancy Moulded Ice Creams	37
Exercise XI
Freezing Custard Ice Cream	41
Exercise XII
Freezing Parfait or French Ice Creams	45
Exercise XIII
Freezing Puddings	49
Exercise XIV
Freezing Ices	52
Exercise XV
Freezing Water Sherbets	54
Exercise XVI
Freezing Milk Sherbets	56
Exercise XVII
Freezing Punches and Lacto	58
Exercise XVIII
Freezing Mousse	60
Exercise XIX
Standardize Mix to a Given Percentage of Fat	62
Score Card for Judging Ice Cream	64
Exercise XX
Judging Plain Ice Creams	66
Exercise XXI
The Effect of Fat Content on Ice Cream	68
Exercise XXII
The Effect of Different Binders on Ice Cream	70
Exercise XXIII
The Effect of Varying Percentages of Milk Solids
Not Fat on Ice Cream	72
Exercise XXIV
Freezing Ice Cream from Raw, Pasteurized, Emulsified
and Homogenized Cream	74
Exercise XXV
The Effect of Aging Cream on the Viscosity and Swell	76
Exercise XXVI
The Effect of the Temperature of the Mix as It Enters
the Freezer on the Swell	78
Exercise XXVII
Effect of the Time of Freezing on the Swell and Quality
of the Ice Cream	80
Exercise XXVIII
Bacterial Counts of Ice Cream	82
Exercise XXIX
Testing Samples of Gelatin	84
Exercise XXX
Trip to Commercial Plants	86
Exercise XXXI
Students’ Receipts	88

260 lbs. 20%	cream	contains	52 lbs.	fat (required).
160 lbs. 30%	”	”	48 lbs.	”
100 lbs. 4%	milk	”	4 lbs.	”
Making a total of			52 lbs.	fat, the amount required.

Date_________________________		Receipt Number_______________

CREAM:		ICE CREAM:
Age	_______	Gallons	_______
Acidity	_______	Weight per gallon	_______
Temperature	_______
		SWELL:
STANDARDIZATION:		Gallons________ Per cent.	_______
Per cent fat in cream	_______
Per cent fat in milk	_______	FREEZING:
Standardize_______	pounds	Freezer used	_______
of cream testing	_______	Pounds ice used	_______
per cent fat.		Pounds salt used	_______
		TIME:
		Of starting freezer	_______
		That mix reaches 30° F	_______
		Required to reach 30° F	_______
		That freezing is completed	_______
		Total time required to freeze	_______

Give proportion.
x = the pounds	_______
Pounds of cream used	_______	TEMPERATURE:
Pounds of milk used	_______	Of mix entering freezer	_______
		Of brine when mix reaches 30° F	_______
MIX:		Of ice cream when removed	_______
Pounds	_______	Of brine at this time	_______
Gallons	_______
Weight per gallon	_______
Per cent fat it should test	_______
Was gelatin used?	_______	By method 1, 2 or 3?	_______
In milk or water?	_______
Remarks:


Comments on ice cream after it is hardened:

Date_________________________		Receipt Number_______________

CREAM:		ICE CREAM:
Age	_______	Gallons	_______
Acidity	_______	Weight per gallon	_______
Temperature	_______
		SWELL:
STANDARDIZATION:		Gallons________ Per cent.	_______
Per cent fat in cream	_______
Per cent fat in milk	_______	FREEZING:
Standardize_______	pounds	Freezer used	_______
of cream testing	_______	Pounds ice used	_______
per cent fat.		Pounds salt used	_______
		TIME:
		Of starting freezer	_______
		That mix reaches 30° F	_______
		Required to reach 30° F	_______
		That freezing is completed	_______
		Total time required to freeze	_______

Give proportion.
x = the pounds	_______
Pounds of cream used	_______	TEMPERATURE:
Pounds of milk used	_______	Of mix entering freezer	_______
		Of brine when mix reaches 30° F	_______
MIX:		Of ice cream when removed	_______
Pounds	_______	Of brine at this time	_______
Gallons	_______
Weight per gallon	_______
Per cent fat it should test	_______
Was gelatin used?	_______	By method 1, 2 or 3?	_______
In milk or water?	_______
Remarks:


Comments on ice cream after it is hardened:

Date_________________________		Receipt Number_______________

CREAM:		ICE CREAM:
Age	_______	Gallons	_______
Acidity	_______	Weight per gallon	_______
Temperature	_______
		SWELL:
STANDARDIZATION:		Gallons________ Per cent.	_______
Per cent fat in cream	_______
Per cent fat in milk	_______	FREEZING:
Standardize_______	pounds	Freezer used	_______
of cream testing	_______	Pounds ice used	_______
per cent fat.		Pounds salt used	_______
		TIME:
		Of starting freezer	_______
		That mix reaches 30° F	_______
		Required to reach 30° F	_______
		That freezing is completed	_______
		Total time required to freeze	_______

Give proportion.
x = the pounds	_______
Pounds of cream used	_______	TEMPERATURE:
Pounds of milk used	_______	Of mix entering freezer	_______
		Of brine when mix reaches 30° F	_______
MIX:		Of ice cream when removed	_______
Pounds	_______	Of brine at this time	_______
Gallons	_______
Weight per gallon	_______
Per cent fat it should test	_______
Was gelatin used?	_______	By method 1, 2 or 3?	_______
In milk or water?	_______
Remarks:


Comments on ice cream after it is hardened:

Proof:

720 lbs. of 25%	cream	contains	180 lbs.	fat.
300 lbs. of 4%	milk	”	12 lbs.	”
420 lbs. of 40%	cream	”	168 lbs.	”
Making a total of			180 lbs.	fat.

		Modification of the
Cornell Score Card		Wisconsin Score Card
Flavor	45	Flavor	40
Body and texture	35	Body and texture	25
Richness	10	Bacterial count	15
Appearance	5	Richness	10
Package	5	Appearance	5
		Package	5

	100		100

Score card used____________________					Date_________________________

	Rec’t #	S C O R E
	Rec’t #	Flavor	C	Richness	Bacteria	D	Package	Total Score	Place	CRITICISMS
A
B
A
B
A
B
A
B
A
B
A
B

Receipts	No. 1	No. 2	No. 3	No. 4
Cream	40 lbs.	35 lbs.	30 lbs.	25 lbs.
	15%	15½%	16⅔%	18%
Whole Condensed Milk		5 lbs.	10 lbs.	15 lbs.
Sugar	8 lbs.	8 lbs.	8 lbs.	8 lbs.
Vanilla	4 oz.	4 oz.	4 oz.	4 oz.
Gelatin	4 oz.	4 oz.	4 oz.	4 oz.
Water	4 lbs.	4 lbs.	4 lbs.	4 lbs.
Per cent Fat
Per cent Milk S. N. F.

Batch Number	1	2	3	4
Pounds of Mix
Gallons of Mix
Temperature of Mix
Time of Starting Freezer
Time of Stopping Freezer
Temperature of Ice Cream
Gallons of Ice Cream
Gallons of Swell
Per Cent of Swell
Comments:

The Project Gutenberg eBook of An ice cream laboratory guide

An Ice CreamLaboratory Guide

LABORATORY EQUIPMENT

EXERCISE NUMBER I

INSPECTION AND STUDY OF ICE CREAM MACHINERY

STANDARDIZATION

EXERCISE NUMBER II STANDARDIZATION

EXERCISE NUMBER III TESTING ICE CREAM FOR FAT

EXERCISE NUMBER IV

EFFECT OF THE SALT AND ICE MIXTURE ON TEMPERATURE

CLASSIFICATION OF ICE CREAM

THE USE OF STABILIZERS

EXERCISE NUMBER V FREEZING PLAIN ICE CREAM

EXERCISE NUMBER VI

METHODS OF MEASURING SWELL

HARDENING ICE CREAM

EXERCISE NUMBER VII FREEZING FRUIT ICE CREAM—HARDENING IN SALT AND ICE

EXERCISE NUMBER VIII NUT ICE CREAM

EXERCISE NUMBER IX BISQUE ICE CREAM

EXERCISE NUMBER X MAKING BRICKS AND FANCY MOULDED ICE CREAMS

EXERCISE NUMBER XI CUSTARD ICE CREAM

EXERCISE NUMBER XII PARFAIT OR FRENCH ICE CREAM

EXERCISE NUMBER XIII PUDDINGS

EXERCISE NUMBER XIV ICES

EXERCISE NUMBER XV WATER SHERBETS

EXERCISE NUMBER XVI MILK SHERBETS

EXERCISE NUMBER XVII PUNCHES AND LACTO

EXERCISE NUMBER XVIII MOUSSE

EXERCISE NUMBER XIX

STANDARDIZE MIX TO A GIVEN PERCENTAGE OF FAT

SCORE CARD FOR ICE CREAM

Discussion of Qualities of Ice Cream

EXERCISE NUMBER XX JUDGING PLAIN ICE CREAM

EXERCISE NUMBER XXI THE EFFECT OF FAT CONTENT ON ICE CREAM

EXERCISE NUMBER XXII THE EFFECT OF DIFFERENT BINDERS ON ICE CREAM

EXERCISE NUMBER XXIII THE EFFECT OF VARYING PERCENTAGES OF MILK SOLIDS NOT FAT ON ICE CREAM

EXERCISE NUMBER XXIV FREEZE ICE CREAM FROM RAW, PASTEURIZED, EMULSIFIED AND HOMOGENIZED CREAM

EXERCISE NUMBER XXV THE EFFECT OF AGING CREAM ON THE VISCOSITY AND SWELL

EXERCISE NUMBER XXVI THE EFFECT OF THE TEMPERATURE OF THE MIX AS IT ENTERS THE FREEZER ON THE SWELL

EXERCISE NUMBER XXVII EFFECT OF THE TIME OF FREEZING ON THE SWELL AND QUALITY OF ICE CREAM

EXERCISE NUMBER XXVIII BACTERIAL COUNTS OF ICE CREAM

EXERCISE NUMBER XXIX TESTING SAMPLES OF GELATIN

EXERCISE NUMBER XXX TRIP TO COMMERCIAL PLANTS

EXERCISE NUMBER XXXI STUDENTS’ RECEIPTS

THE FULL PROJECT GUTENBERG LICENSE

An Ice Cream
Laboratory Guide

INSPECTION AND STUDY OF
ICE CREAM MACHINERY

EXERCISE NUMBER II
STANDARDIZATION

EXERCISE NUMBER III
TESTING ICE CREAM FOR FAT

EFFECT OF THE SALT AND
ICE MIXTURE ON TEMPERATURE

EXERCISE NUMBER V
FREEZING PLAIN ICE CREAM

EXERCISE NUMBER VII
FREEZING FRUIT ICE CREAM—
HARDENING IN SALT AND ICE

EXERCISE NUMBER VIII
NUT ICE CREAM

EXERCISE NUMBER IX
BISQUE ICE CREAM

EXERCISE NUMBER X
MAKING BRICKS AND FANCY
MOULDED ICE CREAMS

EXERCISE NUMBER XI
CUSTARD ICE CREAM

EXERCISE NUMBER XII
PARFAIT OR FRENCH ICE CREAM

EXERCISE NUMBER XIII
PUDDINGS

EXERCISE NUMBER XIV
ICES

EXERCISE NUMBER XV
WATER SHERBETS

EXERCISE NUMBER XVI
MILK SHERBETS

EXERCISE NUMBER XVII
PUNCHES AND LACTO

EXERCISE NUMBER XVIII
MOUSSE

STANDARDIZE MIX TO A GIVEN
PERCENTAGE OF FAT

EXERCISE NUMBER XX
JUDGING PLAIN ICE CREAM

EXERCISE NUMBER XXI
THE EFFECT OF FAT CONTENT ON ICE CREAM

EXERCISE NUMBER XXII
THE EFFECT OF DIFFERENT
BINDERS ON ICE CREAM

EXERCISE NUMBER XXIII
THE EFFECT OF VARYING PERCENTAGES
OF MILK SOLIDS NOT FAT ON ICE CREAM

EXERCISE NUMBER XXIV
FREEZE ICE CREAM FROM RAW, PASTEURIZED,
EMULSIFIED AND HOMOGENIZED CREAM

EXERCISE NUMBER XXV
THE EFFECT OF AGING CREAM ON
THE VISCOSITY AND SWELL

EXERCISE NUMBER XXVI
THE EFFECT OF THE TEMPERATURE OF THE MIX
AS IT ENTERS THE FREEZER ON THE SWELL

EXERCISE NUMBER XXVII
EFFECT OF THE TIME OF FREEZING ON
THE SWELL AND QUALITY OF ICE CREAM

EXERCISE NUMBER XXVIII
BACTERIAL COUNTS OF ICE CREAM

EXERCISE NUMBER XXIX
TESTING SAMPLES OF GELATIN

EXERCISE NUMBER XXX
TRIP TO COMMERCIAL PLANTS

EXERCISE NUMBER XXXI
STUDENTS’ RECEIPTS