Cold Water Straw Fermentation
Cold water fermentation is an easy, fun, DIY technique for treating straw or other substrates for cultivation that doesn’t require the needless waste of wood or fossil fuels!
Simple and scalable, this method is a great technique to have in your toolbox if you’re doing low-tech cultivation. It prevents the cultivator from having to use fossil fuels and emit CO2 and doesn’t require any fancy equipment. Essentially a fermentation process, this method kills off competitors to your spawn by the simple act of submersion in water over a period of days. During the submersion process the anaerobic microorganisms live and grow while all the aerobic (oxygen loving) microorganisms die. When the water is removed after a week, the anaerobic bacteria die as soon as they are out in the open, leaving “clean” straw to use for inoculation. The process is quite simple and goes as follows:
1. Line a garbage can (or any hard, upright container) with a heavy duty (3 mil) trashbag, or find a big barrel that you’ll be able to dump.
2. Fill the bag with dry straw that has (ideally) been chopped with a weed whacker. I don’t personally have a weed whacker so I just break the straw up with my hands. But the increased surface area and smaller pieces provided by the use of this machine will enable better colonization and make handling easier later on.
3. Fill the can with water, covering the straw.
4. Add a weight on top to of the straw to keep it submerged. Big rocks and concrete blocks work well.
5. Put a lid on the can and keep it warm place, ideally in the sun.
6. Wait 7-12 days. If you’re in a warm environment, it’ll go a lot quicker than if you’re in cold environment.
7. At this point the water should be discolored and stinky. This is good, hopefully only anaerobic bacteria are still alive, and these will die when you expose the straw to air. You will now want to extract the straw from the water. If you decided to use a plastic bag inside of the barrel, twist up the top of the bag, poke some holes in it, and let the water drain out.
8. Inoculate your straw with Oyster, Shiitake, King Stropharia, Shaggy Mane, Blewit, or Elm Oyster spawn.