There's a common joke relating workers to mushrooms by keeping them in the dark and feeding them nothing but shit, but the facts are that many mushrooms need a little light, and a lot of them, especially gourmet mushrooms, are wood decomposers. Mycelium, the main body of the mushroom, grows through the wood absorbing the nutrients needed, and the mushrooms fruit out of it.
We started out growing on straw, but for several reasons Andrew dubbed it "Satan's substrate". This is because the Satanic straw makes a huge mess when being processed, so it had to be done outside, making weather a common problem and causing a lot of delays. The chipper didn't like to function properly a lot of days, slowing down our already slow process. The worst thing; however, about the devilish stuff, was the fact that it made Andrew really sick. We're not sure if it was mold spores, the dust, a combination of the two, or something else entirely.
Winter brought the death of our use of Satan's substrate for good. We've replaced it with sawdust, which is better in so many ways. It can be sterilized completely, unlike the pasteurization we did with straw, which cuts down on any contamination risks. More supplement can be put into sawdust, which helps raise the production, and a larger variety of mushrooms can grow on sawdust. The substrate of Satan is mostly limited to growing oysters and other aggressive strains, because slower ones are out competed. Sawdust doesn't provide the competition, allowing us to grow more strains, like Shiitake. Since there isn't as much mess and we don't have to send the sawdust through the chipper, we are able to pack the bags inside, eliminating our dependence on good weather to get work done.
The only downside to using sawdust is the longer time it takes to sanitize it. Our steamer takes 10 hours to get to the heat needed, and then they need to steam for around 12-15 hours, making sanitizing a full day affair.
Learning by trial and error isn't always fun, but it definitely ensures you'll remember the lesson. Over the past year we've learned a lot about mushrooms, and running a business. We've used what we've learned to improve how we do things, and so far the results have been great.