Kids, what is vinegar? Vinegar is a product of the fermentation of alcohol by bacteria to for the purpose of producing acetic acid.  Acetic acid has a tangy taste and it is also useful for household cleaning. Vinegar can be produced slowly from fruit juice or fermented juice. It can be produced quickly by using a culture called Mother of Vinegar which is a slimy, harmless substance of acetic acid bacteria (Mycoderma aceti) and cellulose.

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

Slow Method (Requires 3 weeks to 6 months)

Start with apple cider or fermented fruit juice that contains 0-10% real fruit juice and no added sugar. Either fresh or hard cider will work. Fresh cider takes a few weeks to convert to vinegar because it first ferments into hard cider before becoming vinegar.

Pour the starting liquid into a dark bottle. Fermentation occurs in the dark so you either need a dark container or you need to keep the liquid in a dark place. A clear bottle lets you see what is happening but you need to keep it in the dark the rest of the time. The fermentation process requires air. Cover the mouth of the bottle with a few layers of cheesecloth and secure them with a rubber band, so you don't get insects or dust into your recipe.

Place the container in a dark, warm place at 60-80°F (15-27°C). Fermentation occurs more quickly at a warmer temperature. Initially the bacteria will cloud the liquid, eventually forming a gelatinous layer on the top of the starting material.

Avoid disturbing or stirring the mixture. After 3-4 weeks, smell the covered bottle. Unwrap the cheesecloth if it smells like strong vinegar and then draw off a little liquid, and taste it. Go to the next step if the vinegar passes the taste test. Replace the cheesecloth if you don't like the taste and allow the solution to sit longer. Note: a bottle with a spigot at the bottom makes the taste test much easier, since you can remove a little liquid without disturbing the Mother of Vinegar forming at the top of the container.

Filter the liquid by pouring it through a coffee filter or cheesecloth. The slimy material on the filter is called Mother of Vinegar and can be used to speed the production of future batches. The liquid is the vinegar. Have an adult partner boil the vinegar at 170°F for 10 minutes to kill any undesirable microorganisms and remove residual alcohol (this is called pasteurization). Unpasteurized vinegar is safe but it will have a shorter shelf life (4-6 weeks) and needs to be refrigerated. Pasteurized vinegar may be stored in sealed, sterilized containers for several months at room temperature.

Fast Method (Requires days to weeks)

Add some Mother of Vinegar to the bottle containing the fermented liquid and proceed as before. You can buy unfiltered cider vinegar that contains Mother of Vinegar. Any vinegar you make will contain Mother of Vinegar and can be used to produce subsequent batches of vinegar more quickly.

Reference: Anne Marie Helmenstine at Chemistry.About.com
http://chemistry.about.com/od/foodscienceprojects/a/How-To-Make-Homemade-Vinegar.htm?nl=1

To view all past “ChemShorts for Kids”, go to: http://chicagoacs.org/articles.php?article_category=1

The Primary Education Committee of the Chicago Section ACS presents this column and hopes it will reach young children and help increase their interest in science. Please print it out and pass it on to your children, grandchildren, or elementary school teachers. Teachers are encouraged to incorporate the projects in this column into their lesson plans.