If you’ve been prepping for any length of time, you undoubtedly have several pounds of wheat berries stored away. You may also have experimented with making your own wonderfully delicious bread. The downside of long-term prepping and bread making is keeping active yeast on hand. The average “best by” date on yeast is 2 years. Once opened, it must be kept cool and dry. In a refrigerator, yeast can remain good for up to 4 months; in the freezer for 6 months.
Occasionally there are people who have had success with older yeast, but the bottom line is that store-bought yeast is for short-term. If you have store-bought yeast, stored longer than the above mentioned time frames, follow this simple test to see if it’s still active. A container of yeast that isn’t active anymore should be thrown out.
How to proof yeast
Dissolve 1 teaspoon of sugar in 1/2 C warm water from the tap. Between 110°F-115°F is most effective. The only way to really be sure about the temperature is to use a thermometer. When in doubt, the water from your faucet should be warm but NOT hot to the touch.
Stir in your dry yeast, either one 1/4 oz. packet (7g) or 2 1/4 teaspoons of granulated yeast. Most people say that the yeast should be brought to room temperature first, but I have always had good luck when using it straight from the freezer.
It only takes three or four minutes for the yeast to “wake up” and start to rise. After ten minutes, the surface of your yeast-water mixture should have a foamy top. If so, then congratulations! You have active yeast! It should be used immediately. Most recipes take into account the liquid needed to proof yeast. If yours does not, deduct 1/2 cup of liquid from your recipe if you proof the yeast with this method.
A good way to tell if your yeast has risen sufficiently is to use a 1 C measuring cup. If the yeast foam reaches the top, you’re good to go. If your yeast has an insufficient rise, it will not be any good for baking. Best to throw out the entire container.
Learn how to make your own yeast
If you can’t get to a grocery store for Fleischman’s, what’s the alternative? Try growing your own yeast! Here are a few methods that should fit most needs and skill levels. Depending on the availability of the items listed below, choose one that best fits you, your region, and your personal stockpile.
Raisin / Fruit Yeast
- Clean Glass jar. (24oz. or larger) Sterilize in hot water and allow it to dry.
- Water. Clean, filtered, or bottled is good. Tap water can be used, depending on your local conditions. Warning: Too much chlorine in your water, or water that is too basic, can kill the yeast.
- Raisins or other fruit. Most fruits have traces of yeast on their skins. Note that you may not get as good of a result with fruit that has been washed and waxed.
- Place three to four tablespoons of raisins in your jar. Adding a few tablespoons of honey or sugar will facilitate the fermentation process.
- Fill the jar ¾ full with water. Place the lid on the jar lightly. Do NOT tighten the lid – you will want to allow some air to escape.
- Place jar at constant room temperature. Do not allow the jar to get cold. This will kill off the yeast and stop the process.
- Stir at least once a day for three to four days.
- When bubbles form on the top and you smell a wine-like fermentation you have yeast. The raisins, or fruit, should be floating.
- Place your new yeast in the refrigerator.
Yeast from Grain/ Sourdough Starter
Yeast is already present on grain. All you need to do is to cultivate it in a manner similar to the above instructions. Here is a basic recipe for sourdough starter.
- 1 1/4 C unbleached all purpose flour or milled wheat berries
- 1 C clean warm water
- 1 sterile jar with cheesecloth or lid
- Mix the flour and warm water, and keep at room temperature.
- After several days, the mixture will start to bubble and will begin to rise.
- Keep your starter in the refrigerator when not in use. Use as you would any sourdough starter.
Yeast from Potatoes
The starch in potatoes makes it another prime candidate for yeast production.
- 1 unpeeled medium-sized potato
- 4 C warm water
- 1 tsp salt
- 1 tsp sugar
- 1-quart jar
- Rinse your potato to remove dirt, but don’t scrub it too much.
- Cut it into pieces to facilitate cooking, then boil until cooked through.
- Drain, and save the water.
- Mash the potato and add sugar and salt.
- Allow mixture to cool until it is at room temperature.
- Add water to the potato mash until the whole mixture equals 1 quart.
- Cover and let sit in a warm place and allow it to ferment for several days.
Feeding the Starter
Once you have created your own yeast, you need to “feed” it regularly. This means adding 1 cup flour and 1 cup water to the mix so that the yeast can keep growing. You will need to feed the starter daily if it is at room temperature, or weekly if it is in the fridge. If you don’t bake bread that day, you will also need to toss out one cup of the starter after feeding so that the ratios stay the same. This is an important step, and can be a great motivator to bake regularly so that none of your hard work goes to waste! Yeast starters are one thing you will not want to throw in the compost pile, as the bacteria can grow out of control and give you a very unpleasant result.
No matter which method you choose, making your own yeast is a skill that dates back thousands of years. Continue researching the sources provided to find other ideas, methods, and tips. Begin practicing and post your results. Feel free to add your own ideas and advice in the comment section below.
This article, written by Right Wing Mom, was originally published in 2011. It has been updated and revised.