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Snip open each packet and sift the powdered yeast into your fermenting container. Then, churn the mixture again until the yeast is evenly distributed throughout. The yeast is the key ingredient needed to kickstart the process of fermentation.   As a general rule, you'll need to use 1 packet of yeast for every 20 pounds (9.1 kg) of biomaterial. Distiller's yeast is a special type of yeast that's resistant to alcohol, which makes it perfect for making ethanol. You can find distiller's yeast at any store that carries homebrewing supplies. The exact proportion of water you use will vary depending on the amount of fruits and vegetables you're working with. In other words, you just want to add enough water to cover your biomaterial and keep it moist. The water level should be no higher than 1–2 centimetres (0.39–0.79 in) above the contents of the container.  Use distilled or filtered water, if possible. Ordinary tap water may introduce unwanted chemicals or impurities into your batch of homemade ethanol. Warm or hot water can be used to extract even more sugar from your fruits and veggies. If you're using a barrel or drum that came with a removable lid, simply put the lid in place. Close off makeshift containers by fitting a plastic garbage bag upside down over the opening and taping around the upper edge to prevent air from getting inside. In order for your raw biomaterial to ferment successfully, it's important to make sure that your container has been properly sealed. In most cases, it will take somewhere between 7 and 10 days for the sugars in your fruits and veggies to break down completely. During this time, avoid opening the container for any reason, unless it's to monitor the sugar content of your biomaterial. As your raw biomaterial sits, the yeast will feed on its natural sugars, producing simple alcohol, or ethanol, as a byproduct. Open your fermenting container and insert the tapered end of the hydrometer into the liquefied biomaterial. You should notice the resulting sugar reading (most often denoted in ounces per gallon, “Balling,” or “Brix”) decreasing a little more each day. After 7-10 days, there should be no sugar left whatsoever, which means the fermentation process is complete.  Pick up a hydrometer when you go to buy your distiller's yeast. You may also be able to find one of these tool at a store that sells specialty cookware. Your biomaterial may ferment in more or less time, which is why it's recommended that you keep an eye on the sugar content rather than following a set timetable.

Summary:
Mix 1-2 packets of distiller's yeast in with your biomaterial. Add clean water to the top of the mixture. Cover your fermenting container securely. Allow your biomaterial to ferment for at least 1 week. Use a hydrometer to check the sugar contents of your biomaterial daily.