Saccharomyces cerevisiae, or brewer's yeast, is the strain of yeast used in brewing beer. When it's mixed with sugar, water, hops and grains, yeast grows and ferments, producing the alcohol in beer. In a similar manner, gardeners mix brewer's yeast with sugar and warm water before adding the solution to the compost pile to accelerate the decomposition process. As the yeast grows and ferments within the organic matter, it breaks the cellulose down rapidly, producing an ideal environment for bacterial growth. The bacteria produces water, carbon dioxide and heat, warming the compost pile rapidly to 120 to 140 degrees Fahrenheit.
Items you will need:
Rake the dry leaves and twigs into a pile. Chop into small pieces by running a lawnmower with a bag attachment over the pile. These are the dry, or brown, ingredients. Store in a garbage can or garbage bags until you mix the compost.
Save the grass clippings when you mow the lawn. Empty the lawnmower bag into a garbage can and set aside until you're ready to mix your compost. These are the wet, or green, ingredients.
Chop your kitchen scraps into small pieces and place in a covered container, such as a 5-gallon bucket. Add coffee grounds, potato peels, crushed eggshells, onion skins and other waste to the bucket.
Mix a solution of 1 cake of brewer's yeast, 1 cup of sugar and 1 gallon of 105- to 115-degree-Fahrenheit water in a bucket. Stir the ingredients together, then set aside while you mix the compost.
Mix equal parts brown and green ingredients on a tarp next to a plastic compost bin. Add shredded paper, cardboard or sawdust if more brown ingredients are needed to balance the mixture. Add small amounts of steer or chicken manure if more green ingredients are needed.
Add the kitchen scraps to the compost ingredients. Mix the compost with a shovel or pitchfork.
Shovel the compost into the compost bin. If the compost is dry, sprinkle with water to moisten the ingredients.
Pour the brewer's yeast solution over the compost ingredients. Cover the bin.
Test the compost's moisture level daily in hot weather by squeezing a handful of the compost. If it's warm and moist, it doesn't need additional solution. If the compost is dry, slowly add water with a garden hose while you mix more yeast solution. Remove the hose and pour the yeast solution over the dampened compost.
Check the temperature of the compost with a commercial kitchen thermometer every two days. When the compost reaches 120 degrees F, stop adding the yeast solution. At this point, use only water to hydrate the compost until it matures into crumbly, dark brown humus, in two to three months.
Turn the compost once a month. Many compost bins disassemble, making it easy to remove the compost, reassemble the bin and shovel the compost back into the bin. Otherwise, tip the bin onto its side and dump the compost onto a tarp. Shovel the compost back into the bin.
- If you make home-brewed beer, add the waste grains, hops, yeast and trub to your compost pile.
- Use a recycled plastic food-grade barrel instead of a compost bin. Drill drain holes in the bottom and sides of the barrel before adding the compost.
- A compost bin or barrel is not necessary for composting; simply pile the compost in a corner of the yard, near the garden.
- Use your homemade compost to make a compost tea for your potted plants.
- Wear gloves, safety glasses and a dust mask when mowing and shoveling the compost ingredients.
- Don't add cat or dog manure to the compost bin; it may harbor parasites and pathogens that will contaminate your compost.
- RAMIRAN-Research Network on Recycling of Agricultural and Industrial Residues in Agriculture: Composting of Brewery Wastes With Agricultural and Forest Residues
- The Society for Applied Microbiology: Letters in Applied Microbiology: The Influence of Yeast on Thermophilic Composting of Food
- USDA National Organic Standards Board: Compost Tea Report
- The Presidio Trust: The Effects of Compost Tea on Golf Course Greens Turf and Soil: Presidio Golf Course, San Francisco CA
Ruth de Jauregui is the author of "The Soul of California—Cooking for the Holidays," "Ghost Towns" and "100 Medical Milestones That Shaped World History." A graphic artist and writer for more than 20 years, she maintains several blogs and is currently working on her first fiction novel.
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