Week Four: Diversifying

Incubator full of different grain and mushroom strain combinations.

This week we refined our process of the liquid culture.  After our first attempt last week we observed that a mystery solid (not the mycelium) had formed in the bottom of the jar and mixed with the V.volvacea culture.  Since we could no longer differentiate the culture we decided to start over.

We made two separate sugar broths, one with malt and one with the dextrose, to determine which ingredient had caused the problem. After pressure cooking our two mixtures the dextrose solution was completely clear while the malt solution contained some particles at the bottom. We decided to scrap the malt solution and the malt/dextrose solution and inoculated the broth of distilled water and dextrose.

Dextrose and water solution and malt and water solution after pressure cooking.

We soaked and boiled two grains this week: sorghum and millet.  Due to our fear of overcooking the millet again, we didn’t bring the grains to a full rolling boil and instead simmered them for about 10 minutes.  We let them sit spread out on a towel to dry for about four hours and then put them in mason jars.

We tried pressure cooking five jars, two of sorghum and three of millet, but the cooker ran dry after about 40 minutes so we turned off the heat and let it depressurize.  Upon opening the pressure cooker, we found that the insides of our jars were covered in condensation and the grains were clumped together, so we realized that we hadn’t let the grains dry thoroughly enough before jarring.  We emptied all the jars and dried the grains using paper towels. As we did so, we noticed that the sorghum that had been pressure cooked was darker compared to one jar we hadn’t had room for in the cooker. Our hypothesis is that the grains had not been cooked fully when before being sterilized because we hadn’t brought the pots to a full boil, and that the time spent in the pressure cooker with water had cooked them instead.  After drying the grains, we repacked them and tried sterilizing them again.

Again, we ran into the issue of the cooker running dry - this time after a full hour.  We let it depressurize, added more water, and then continued sterilizing for the last half hour.  The next day we inoculated a jar of millet and a jar of sorghum with two plugs of oyster mushroom mycelium.  We did the same for two other jars of millet and sorghum using silk straw mushroom plugs. Finally, we cut pieces of the oyster mushroom agar culture and put them in a jar of millet.