Buzz
Creating yeast may initially appear daunting due to its precise steps, equipment, and ingredients, but it's actually a straightforward process! With just a few common kitchen tools and household items, you can culture yeast at home. Though it requires some time and attention to detail, mastering the technique allows you to produce yeast whenever needed for baking bread, brewing beer, or preparing various delicious dishes that rely on yeast.
Procedure
Yeast Cultivation from Malt Extract
Initial Heating: Preparing the Medium
Boil 1 cup (250 ml) of water. Once boiling, remove from heat.
Dissolve 15 grams (1/2 ounce) of malt extract in the water. Boil for an additional 10-15 minutes to ensure sterility.
- This second boiling sterilizes the mixture, known as 'wort.'
Mix a packet of gelatin into the wort. Stir until fully dissolved.
Divide the gelatin-wort mixture into your culture containers. Fill each about 1/4 inch full, using a sterilized funnel for ease, especially with test tubes or vials.
- Keep one container empty for later in the culturing process.
Inoculating the Medium: Second Heating
Position jars or dishes at the base of the large stockpot. Ensure it's lidded! Flat-bottomed vessels are ideal. If you're using tubes with rounded bases, you'll need to prop them up to stand.
Fill the dish with 2 to 3 inches (5 - 7.5 cm) of water. Ensure it reaches halfway up the sides of your culturing vessels. Be cautious not to let water enter the jars.
- Carefully place the jar lids inside without sealing them; this sterilizes them. Sealing them may cause pressure buildup and potential explosions.
Bring the water in the stockpot to a boil. Maintain high heat for 15 minutes to sterilize the culturing vessels. Then, use kitchen tongs to remove vessels and allow them to cool completely. This cooling process may take some time, so exercise patience.
- Ensure the vessels cool to at least 40°C before sealing with sterile caps to avoid deformation or implosion due to temperature differentials. Once cooled, firmly secure the caps. Many brewers prefer to let them cool at an angle, known as 'slants,' for about 24 hours.
- Home brewers often use test tubes, which they tilt to solidify the wort-gelatin mixture at an angle, hence the term 'slants.'
Final Steps
Prepare your workspace. Gather all necessary items within reach before starting the process. You'll need:
- Yeast packet
- Slant vials
- An unwrapped paper clip or long needle
- Cotton ball or folded paper towel
- Bottle of ethyl alcohol
- Clean paper towel for your starter vessel
- An empty, sterilized slant vial with its cap
Follow the yeast preparation instructions on the package. Each package provides specific guidance, so adhere to it closely. Shake the yeast to create a paste-like consistency.
Initiate the culturing process for your slants. Open the yeast packet halfway. Wipe the needle or paper clip with an alcohol swab to sterilize it and remove potential contaminants that could hinder yeast culturing.
- Draw a small amount of yeast paste into the needle or coat the paper clip by swirling it in the yeast packet.
Inject the yeast into the gelatin mixture through the needle. Work swiftly to minimize the risk of contamination. Minimize breathing during this step if possible.
- Some brewers suggest placing an alcohol-soaked paper towel over the jar or dish opening and inserting the needle or paper clip through it to prevent contamination during yeast insertion.
Securely seal the jars or dishes. Store them in a clean, cool, dark location for 72 hours. Within a few days, a cloudy film will form on the slant surface, evolving into a milky white layer approximately 1 mm thick shortly after.
- Wipe the jars and lids exterior with alcohol swabs to ensure complete sterility.
Slightly loosen and retighten each jar to release built-up pressure.
- You'll hear a faint hissing noise as the seal breaks, allowing excess carbon dioxide produced by yeast growth to escape and lower jar pressure.
Date each jar to track the culturing process. Store in a clean refrigerator to foster ongoing culture growth. They'll remain in optimal condition for at least 3 months.
Creating Yeast Starter using Potatoes
This method offers a way to produce yeast without relying on a yeast package. The recipe provided suits larger families requiring multiple loaves for baking purposes.
Cook 1 medium potato in unsalted water until tender. Drain, preserving the water.
Mash the cooked potato. Incorporate 1 teaspoon of sugar and a pinch of salt.
Allow to cool to lukewarm temperature. Mix in adequate potato water to create one quart of mixture.
Cover and place in a warm environment. Let it ferment.
- Note: If the starter isn't rising, you can accelerate the process by adding a store-bought yeast package. However, it will ferment just as well without the additional yeast.
Helpful Tips
Essential Supplies
- Water
- Large pot with lid
- Malt extract
- Gelatin
- Petri dishes, canning jars, or baby food jars with lids
- Tongs
- Packet of yeast
- Alcohol swabs
- A hypodermic needle or a straightened paperclip
