Bread as a growing Medium?

I'm new to mushroom growing in general, but I've read of people using bran as a substrate or growing medium, and I was wondering if bread would work well.  I have access to large amounts of discarded bread and aside from croutons and the occasional treat for chickens, I haven't been able to think of many good uses for it.  Furthermore, it's a pretty common material so I think if it's a good option, it would be relevant to a lot of people.

If it would work, what preparation might be necessary (shredding, amending with other stuff, etc.)?  Any idea what species might work well (or not work well) in this type of setup?

A lot of growers use grain as their starter substrate then move the shrooms to wood substrate for ripening. I don't see any reason why bread shouldn't work; doubtful it'd be as kind to your fungi as whole grain mash, though.. unless you're milling fresh flour and baking it yourself, or buying it in from someone who does.

Awesome to hear... Most of the bread I pick up would be made from "organic wheat and rye flours" and it's from a bakery that's almost 100% 'organic,' not sure if that qualifies as milling fresh flour and baking it myself, but I'd guess it's better than wonder bread...

Grain is not a natural medium for growing mushrooms. It is a rich source of nutrients, which bacteria, mold and yeast are much better at quickly exploiting than the edible fungi. When we use grain as a starter, it is typically sterilized in a pressure cooker for 90 minutes at 15 psi to kill all the competing organisms, then it is inoculated in a sterile environment with the desired fungi.

Many different grains are used for mushroom spawn, but my favorite is rye, because it is the easiest to properly hydrate. If you get too little or too much water in the grain, the mycelium will not grow properly.

I've never tried using bread as a starter, but I imagine the biggest obstacle is the texture - it seems to me that the bread would become a big gloppy mess if one moistened it and pressure cooked it. It might be worth trying several different "recipes" to see if a proper water to bread ratio is achievable.

I use wheat bran as a nutritional supplement (along with gypsum) for the sawdust fruiting blocks that are sterilized for two hours at 15 psi. I see no reason that bread could not be substituted for wheat bran in these blocks.

I've heard that a good use for old bread is as an ingredient in new bread (but I've never tried it.)

frankenstoen wrote:
Grain is not a natural medium for growing mushrooms. It is a rich source of nutrients, which bacteria, mold and yeast are much better at quickly exploiting than the edible fungi. When we use grain as a starter, it is typically sterilized in a pressure cooker for 90 minutes at 15 psi to kill all the competing organisms, then it is inoculated in a sterile environment with the desired fungi.

Many different grains are used for mushroom spawn, but my favorite is rye, because it is the easiest to properly hydrate. If you get too little or too much water in the grain, the mycelium will not grow properly.

I've never tried using bread as a starter, but I imagine the biggest obstacle is the texture - it seems to me that the bread would become a big gloppy mess if one moistened it and pressure cooked it. It might be worth trying several different "recipes" to see if a proper water to bread ratio is achievable.

I use wheat bran as a nutritional supplement (along with gypsum) for the sawdust fruiting blocks that are sterilized for two hours at 15 psi. I see no reason that bread could not be substituted for wheat bran in these blocks.

I've heard that a good use for old bread is as an ingredient in new bread (but I've never tried it.)

Great points, thanks for your input.  I get the impression from your comments and my own research that it would be allowable and more useful in moderation as a supplement, rather than the primary medium.

This isn't fungi related, but my other plan for the excess bread is to combine it with sugar and water to activate Effective/Beneficial Microorganisms.

Some people have been known to mix a little bit of sawdust into their grain to help balance the moisture levels and to keep the kernels from clumping in the spawn. Perhaps a mixture of sawdust and bread, or grain and bread, (or all three) could achieve a substrate with a texture that the mycelium will enjoy.

If you have the time and resources, experimentation is always worthwhile.

fungenstoen has good points.  I don't doubt you could grow vigorous species like oysters on bread but it might be better as a supplement.  I think the tricky part would be getting the moisture content right - you don't want it to get soggy but sufficiently moist.

Also, not fungus-related but another idea for what you could do with that old bread is bread pudding.