Week Two: Grains

Wheat grains after 24 hr soaking and 10 min boiling.

This week we made our first attempt at producing grain spawn.  First, we soaked barley, millet, and wheat, each mixed with used coffee grounds, in three separate pots for 24 hours.  After this, we boiled the grains for approximately ten minutes. The millet was over cooked, but the barley and wheat were still intact.  We let the two dry, speeding up the process using a hair dryer, and then jarred them into quart sized mason jars.

We also made filters in the lids of the jars.  For this, we used a pen and a hammer to create a 3/16” hole in the lid and stuffed this hole with polyfil.  This is an important aspect of the jars because the filter allows for the CO2 produced by mycelial growth to escape while also preventing bacteria from contaminating the jar.

Jarred wheat and barley with filtered lids before pressure cooking.

The next step was pressure cooking the jars.  Our pressure cooker was a little small for the quart jars, so we took the tray out of the bottom and only placed three jars inside.  We put about a half inch of water in the cooker and let it cook at 15 psi. We planned to let it cook for 90 minutes, however a little over halfway through disaster struck.  We started to smell something burning so we turned off the heat and let the cooker depressurize overnight. In the morning we opened it up and found our jars had cracked and the grains had burned.

We hypothesize that the pressure cooker ran dry due to a shortage of water.  We also assume our jars were too large for the cooker and that taking the tray out of the bottom exposed the jars to too much direct heat.  For our next attempt, we plan to purchase smaller jars and add a larger quantity of water before sterilization. We will start from scratch next week with new grains.

This week we also utilized petri dishes with an agar medium in order to grow our spawn.  On one plate we placed an entire plug with P.osterous mycelia and on another we scraped of the mycelia and added it directly to the petri dish using a sterile scraper.  We have already seen slight growth and expect to observe this continuous trend. The agar medium will act as a “food” source allowing the mycelia to “run” or grow.

Oyster Mushroom mycelium on agar plates.