This past week I tried the sawdust test with a 10 gram sawdust sample – like baking a cake.
I spread it out on a pan and put in the oven for around 5 hours.
afterwards, the sawdust weighed in at 9.28 grams.
Although, I was concerned that some of the sawdust was still stuck to the pan. Wasn’t sure the best way to get all the sawdust off. Could also repeat with a larger amount where the residue is less of a factor.
^ image of sawdust residue stuck to pan at the end
for the first time we also tried just adding distilled water to our sawdust while innoculating it to fine-tune it up to field capacity by touch. this felt good. since the waste sawdust we use is slightly different each time from the woodshop we source it from, the moisture test might not give us perfect information (unless we repeat it with each batch).
for some reason, we’d never tried adding extra distilled water at the end… makes a lot of sense doing this instead of trying to guess/estimate the water content exactly with variable inputs, and I’m feeling quite optimistic this can help us improve our technique. Basically we pasteurize the sawdust in a cooler with a pour-over of boiling water which is roughly the right amount to hydrate it (we’ve been using 40% of water volume to sawdust volume) and then we can just add a little water the next day while innoculating to get it fully to field capacity. Also planning to switch to calculating the initial water amount by weight of sawdust instead of by volume of sawdust, as I think that might also give us a slightly more reliable starting point. That’s the long sawdust-moisture update.