Hi Steve, welcome to the forum.
Don't quote me, but I suspect that brewers yeast powder is essentially spent brewers yeast I believe (that doesn't make real sense as it just multiplies), but is killed with heat. The theory being that the nutrients are there but it is not an active yeast any more.
Not sure that fermenting bees are a good thing.
Very good as a source of rich nutrition, for people, horses and bees as a supplement.
Some beekeepers feed pollen patties or pollen substitute patties in the early spring, made from soya flour, brewers yeast powder, sugar and irradiated pollen or pollen from your own bees where the risk of disease is limited.
pollen, unless irradiated, or honey from other sources is a definite no, no. Spores of AFB, EFB or other pathogens can be present and while totally safe for humans are vectors for bee diseases.
The patties give the bees the protein that they need to raise brood ready for the early nectar flows. I am about to put patties on my bees this coming week with a view to giving them a chance to build up strongly as they come into the spring.
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I hope someone will be along in the morning to give you an assist with looking into their boxes of bees. Enjoy.