Analytical Chemistry Experiment

Preparation of Alcoholic Beverages from Fresh Fruits

Abstract

About one kilogram of Pineapple was washed, peeled and cut off in small cube to osterize in a blender. A fruit extract was obtained. Together with the addition of desirable amount of sugar and yeast, the fruit extract was placed in a high-neck bottled and been fermented for at least two weeks. It was been pastured through the use of traditional katsa (filter).  Pineapple wine was produced and placed to observation about its taste, color, odor, textured and transparency . 100ml of the wine with raisins was set aside for distillation and boiling point experiments…

I. Introduction

Fermentation come form a Latin word fermentum means to leaven. Fermentation is the anaerobic enzymatic conversion of organic compounds, especially carbohydrates, to simpler compounds, especially to ethyl alcohol, resulting in energy in the form of adenosine triphosphate (ATP); the process is used in the production of alcohol, bread, vinegar, and other food or industrial products. It differs from respiration in that organic substances rather than molecular oxygen are used as electron acceptors. Fermentation occurs widely in bacteria and yeasts, the process usually being identified by the product formed; e.g., acetic, alcoholic, butyric, and lactic fermentation are those that result in the formation of acetic acid, alcohol, butyric acid, and lactic acid.

On the other hand, fermentation can also define as the conversion of a carbohydrate such as sugar into an acid or an alcohol. More specifically, fermentation can refer to the use of yeast to change sugar into alcohol or the use of bacteria to create lactic acid in certain foods. Fermentation occurs naturally in many different foods given the right conditions, and humans have intentionally made use of it for many thousands of years.

II. Review of Related Literature

Alcoholic Beverages

May be divided into fermented drinks including beer and wines, and distilled drinks or spirits which are obtained from the former by distillation. Spirits usually contain about fifty per cent. of alcohol, beer and wines from one to twenty per cent. The alcohol in all cases results from the breaking up of the sugar in the fermenting liquid.

Sugars

Ordinary sugar, or cane sugar, uncrystallizable, or fruit sugar; and grape sugar, or glucose, are the three most important varieties. Fruit sugar exists in all the sub-acid fruits as grapes, currants, apples, peaches, etc. When these are dried, it changes to grape sugar forming the whitish grains which are seen on the outside of prunes, raisins, etc. Grape sugar is found to a limited extent in fruits associated with fruit sugar. Cane sugar is readily changed by the action of acids or ferments into fruit sugar, and the latter into grape sugar, but the process cannot be reversed. Grape sugar is the only fermentable variety, the others becoming changed into it before fermentation.

Transformation of Starch

Under the influence of acids, or diastare, a principle existing in germinating grains, starch is changed first into gum (dextrine) and afterwards into grape sugar. Hence one of our most important sources of alcohol is to be found in the starch of barley, corn, wheat, potatoes, etc. Wood may be converted into grape sugar by the action of strong sulphuric acid which is afterwards neutralized. An attempt to produce alcohol in this way on a commercial scale was made in France, but was not successful.

Ferment

A solution of pure sugar will remain unchanged for an indefinite period of time. To induce fermentation, a portion of some nitrogenous body, itself undergoing decomposition, must be added. Such ferments are albumen (white of egg), fibrin (fibre of flesh), casein (basis of cheese), gluten (the pasty matter of flour). Yeast consists of vegetable egg-shaped cells, which is increased during its action as a ferment.

Circumstances influencing Fermentation

In order that fermentation shall begin we require, besides the contact of the ferment, the presence of air. The most easily decomposed articles of food may be preserved for an indefinite period by hermetically sealing them in jars, after drawing out the air. When once begun, however, fermentation will go on, if the air be excluded. Temperature is important. The most favorable temperature is between 68 and 77 Fahr. At a low temperature fermentation is exceedingly slow. Bavarian or lager beer is brewed between 32 and 46 1/2 Fahr. A boiling heat instantly stops fermentation, by killing the ferment.

To check fermentation we may remove the yeast by filtration. Hops, oil of mustard, sulphurous acid (from burning sulphur), the sulphites, sulphuric acid, check the process by killing the ferment.

Too much sugar is unfavorable to fermentation, the best strength for the syrup is ten parts of water to one of sugar.

Changes during Fermentation

The grape-sugar breaks up into carbonic acid which escapes as gas, alcohol and water which remain. In malting the grain is allowed to germinate, during which process the starch of the grain is changed into gum and sugar: the rootlets make their appearance at one end and the stalk or acrospire at the other. The germination is then checked by heating in a kiln; if allowed to proceed a certain portion of the sugar would be converted into woody matter, and lost.

In brewing the sacharine matter is extracted from the malt during the mashing. Yeast is added to cause fermentation; an infusion of hops afterwards, to add to the flavor and to check fermentation. In wine making there is sufficient albuminous matter in the grape to cause fermentation without the use of yeast.

Distillation separates the alcohol in great part from the water. Alcohol boils at 179 Fahr., and water at 212. It is not possible, however, to separate entirely alcohol and water by distillation.

(The Household Cyclopedia of General Information, 1881)

III. Methodology

A.     Preparation of Juice Extract

1.)    Wash 1k of fruit. Peel off skin, or remove the seeds or pits when present. Cut small cubes, and osterize into a smooth consistency using a blender.

2.)    Add boiled water (cooled before adding). If the fruit extract obtained is viscous or too thick in consistency.

3.)    Add about brown or white sugar (amount added is relative to your taste) as he fruit is osterized and mixed thoroughly.

4.)    Transfer the juice into a high-necked bottle and cover tightly.

B.     Fermentation

1.)    Follow the set-up given by the instructor.

2.)    Add about 2 tablespoons of yeast to the fruit extract.

3.)    Allow fermentation of the mixture for 2-3 weeks.

C.     Pasteurization

1.)    Using clean cheesecloth (katsa), filter the fermented mixture, receiving the filtrate in a clean container.

2.)    Warm the filtrate to about 60-65 C. Add raw egg white and stir until the egg white is cooked. The egg white acts as a coagulant for any left-over residue in the filtrate.

3.)    Filter the cooked mixture again, using the cheesecloth. Dispose any coagulated substance retained by the cloth.

4.)    Place a small amount of the fermented mixture in a clean container and observe the following properties:

a.) taste                               b.) color               c.) odor                                d.) texture          e.) transparency

5.) Set aside 100ml of the fermented mixture for the distillation and boiling point experiments. Keep this portion in a tightly sealed bottle and refrigerate.

IV. Discussions of Data and Interference from Results

After doing the experiment, we observed the following properties:

Taste	Sweet pineapple taste with pinch of an alcoholic taste.
Color	It comes in bright yellow in color.
Odor	Strong Pineapple.  Too much smell can make you feel dizzy.
Texture	It was just fine.
Transparency	It comes in a slimy bright yellow .  I think sugar is the cause why it is slimy.

The wine was alcoholic because of the sugar or glucose that was broken down by the yeast. Without the presence of oxygen, the product of the glucose becomes ethyl alcohol and carbon dioxide.

V. Answers to Guide Questions

1.) Write the balanced chemical equation that represents the fermentation of sugar.

C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂

This chemical equation summarizes ethanol fermentation, in which one hexose molecule is converted into two ethanol molecules and two carbon dioxide molecules

2.) What is the role of the yeast in the process?

Yeast are unicellular fungi that reproduce asexually by budding or fission. Yeast is what causes primary fermentation to take place. The role of yeast in the chemical process is that it will eat the sugars in the pineapple juice and the end products are CO2 and alcohol.

3.) Why should the fermentation set-up be alright?

Set-up should be alright in order to have accurate result of the experiment since fermentation is an anaerobic process, and oxygen will cause the organisms to produce different products.

If the set-up for fermentation is not properly assembled, like if the cover in the set-up is not properly sealed, the result of the fermentation may be contaminated or worse if the fermentation process will not take effect because of the presence of oxygen converting glucose to carbon dioxide and water.

4.)    What is the use of the limewater in the process?

Lime water also known as  saturated calcium hydroxide solution Ca(OH)₂ can be used to test the presence of carbon dioxide because lime water reacts with carbon dioxide to produce a precipitate of calcium carbonate:

Ca(OH)_{2 (aq)} + CO_{2 (g)} → CaCO_{3 (s)} + H₂O _(l)

Lime water is also used in fermentation, to determine whether carbon dioxide was produced. When lime water reacts with CO₂ it becomes milky.

5.) What must be the average pH of the product of fermentation to qualify as “alcoholic”?

The resulting alcohol is 100 to 200 proof (200 proof is pure alcohol). Yeasts are able to grow in foods with a low pH, (5.0 or lower) and in the presence of sugars, organic acids and other easily metabolized carbon sources.

VI. Bibliography

• Zubrick, James W. The Organic Chemistry Lab Survival Manual: A Student’s Guide to Techniques 6th Edition. New York: John Wiley & Sons Canada, Ltd.; 5th edition.

• http://en.wikipedia.org/wiki/Fermentation

• Dorland Medical Dictionary, http://www.mercksource.com

• What is Alcoholic Fermentation, http://www.publicbookshelf.com/alcoholic.html

Technorati Tags: Alcoholic Beverage, Analytical Chemistry, Experiment, Fermentation, Pasteurization, yeast

Analytical Chemistry Experiment

Simple Distillation Method

Abstract

A quick fit set-up for simple distillation was been assembled carefully. 50ml of Pineapple wine was placed in a pear shaped flask and added with boiling chips. Making sure that water was flowing in a condenser, the wine sample was heated with a burner using one inch blue flame. Four distillate with recorded temperatures were collected. These distillates were kept for boiling point experiments…

Introduction

The boiling point of a pure organic liquid is a physical property of that liquid. It is defined as the temperature at which the vapor pressure of the liquid exactly equals the pressure exerted on it. Boiling points can be determined using the technique of simple distillation. Distillation is a technique that is used to purify a mixture of liquids or to obtain a boiling point of a pure liquid (in the case of this course). Essentially, the liquid is heated to boiling and the vapors condensed above the boiling liquid.

Distillation is a very old technique which is frequently used to purify compounds and to determine their boiling points. The boiling point is a useful molecular constant for the characterization and identification of pure compounds. Furthermore, the boiling point range is usually a good indicator of the purity of a liquid.

Distillation is a physical process used to separate mixtures that contain at least one liquid. Distillation works because each substance in the mixture has its own unique boiling point. So, as a mixture is heated, the temperature of the mixture rises until it reaches the temperature of the lowest boiling substance in the mixture. The lowest boiling substance boils away. Meanwhile, the other components of the mixture remain in their original phase (either solid or liquid) until the lowest boiling component has all boiled off. Only then does the temperature of the remaining mixture rise and other components are boiled off.

I. Review of Related Literature

Distillation often follows fermentation. Fermentation is used to produce alcoholic beverages. Grain is fermented to make beer, while grape juice is fermented to make wine. Beer and wine never contain more than around 12% alcohol, because any higher concentration kills the yeast that produce the alcohol. To make stronger drink, distillation is used. Wine, beer, or fermented brews made from corn, sugar cane, or potatoes can be purified by distillation. Since ethyl alcohol boils at only 83°C while water boils at 100°C, the alcohol will boil off, leaving the water behind. The alcohol vapors are then condensed and collected. Distillation can produce liquors that range from 40-95% ethyl alcohol.

The object of distillation is the separation of the alcohol from the other ingredients in the beer, mostly water. In making fuel alcohol it is necessary to get all of the alcohol and water separated if the alcohol is going to be mixed with gasoline, and most of the alcohol and water separated if the alcohol is going to be burned in a converted engine. As will be seen, the purer the alcohol, the harder it is to make.

The separation of the alcohol and water by distillation is made possible by the fact that alcohol boils at about 173 degrees F. and water at 212 degrees F. When the mixture of water and alcohol is boiled, vapors with a greater concentration of alcohol will be formed and liquid with a lesser concentration of alcohol will remain behind. However, because water and alcohol do not form what is called an “ideal” mixture, the separation cannot be done in one clean step.

Figure Simple Distillation

It illustrates a simple distillation apparatus using laboratory-type equipment. Note that the equipment consists basically of a container for the liquid to be distilled (still pot), a heat source, and a condenser to turn the distilled vapors back into liquid form. The thermometer is necessary to monitor the temperature of the vapors.

II. Methodology

1.)    Carefully assemble the quick-fit set-up.

2.)    Place 50ml of the liquid sample in the pear shaped flask. Add a few pieces of boiling chips.

3.)    Make sure the water is flowing through the condenser. Heat the sample with a burner, using a one-inch blue flame.

4.)    Collect the distillate in labeled test tubes, recording the temperature. Change the test tube after collecting 5 to 10 drops. Keep the distillate for the boiling point determination.

5.)    When done, cut off the heat source first, before closing the water valve.

6.)    Allow time for the set-up to cool before dismantling the glassware.

III. Discussions of Data and Interference from Results

The data below are from the collected fractions of distillates from the liquid sample. Every fraction contains 1mL of the distillate. We used a test tube containing 1mL of distilled water to compare it with our fraction to know if it contains the right amount of volume we wanted.

	Volume of fraction collected	Temperature	Flame test result
Fraction 1	1mL	°C	Not Tested
Fraction 2	1mL	°C
Fraction 3	1mL	°C
Fraction 4	1mL	°C

The first fraction we collected with 1mL of the distillate was at __°C, the second at __°C  third at __°C  and the last is at __°C . We didn’t tested the first fraction if it is flammable or not to know if the distillate was an ethanol or not since our instructor not ask to do it so. But as far as the temperature values are concerned since they are closed to the accepted values boiling ethyl alcohol, I can say that the product is an ethyl alcohol.

IV. Answers to Guide Questions

1.)    Where should the thermometer bulb in the distillation setup be placed and why?

The thermometer should be placed above the liquid sample where the vapor is passing. In this case, we can determine the temperature of the vapor and not the liquid sample.

2.)    How can one know that a component of liquid mixture has been completely vaporized and distilled over?

One can know that a component of liquid mixture has been completely vaporized and distilled over if, the vapor from the liquid sample turned to pure liquid.

3.)    What is the advantage of a fractional distillation over the simple distillation type?

The advantage of fractional distillation over the the simple distillation type is that, in fractional distillation, the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate.

While in simple distillation, all the hot vapors produced are immediately channeled into a condenser which cools and condenses the vapors. Therefore, the distillate will not be pure, its composition will be identical to the composition of the vapors at the given temperature and pressure.

V. Bibliography

• Zubrick, James W. The Organic Chemistry Lab Survival Manual: A Student’s Guide to Techniques 6th Edition. New York: John Wiley & Sons Canada, Ltd.; 5th edition.

• S.W. Mathewson, “The Manual for the Home and Farm Production of Alcohol Fuel” http://journeytoforever.org/biofuel_library/ethanol_manual/manual11.html

• “Distillation”, http://en.wikipedia.org/wiki/distillation.html
• “Elements, Compounds and Mixtures”, http://www.gcsescience.com/distillation.html

Technorati Tags: Analytical Chemistry, Distillation, Experiment, Simple Distillation