
It is my observation that in all malt recipes, and even bourbon recipes with 20-30% malt, yeast health is rarely an issue. The explanation is hidden in the magic that happens when a seed germinates, enzyme production to so much more.
But more and more people are doing ALL GRAIN mashes with 100% raw grain and using a variety of lab produced enzymes for the conversion. It is my observation that these raw grain and enzyme based mashes do not ferment happily all the time and are more prone to stalling and infections. In another post Booner commented that an all corn mash done with enzymes just doesnt have the goods to make the yeast happy. I completely agree, and have had to really nurse all corn mashes along to get them to finish well, and have plenty of failures along the way too. Booner suggests prenatal vitamins crushed up for corn. I havent tried that yet but I will. Here's my suggestions for yeast health for these finicky enzyme based mashes. The sugarhead guys have some tricks too in their threads, see RAD and others for related info on sugarheads using vitamins, fertilizer, tomato paste etc.
DONT use anything urea based. Often they are marketed as Yeast Energizer. Urea reacts with ethyl alcohol to produce Ethyl Carbamate. Its a carcinogen, and is getting quite a bit of attention in the industry at the moment. So whether or not it comes over in the distillate or not, I dont much care. Its not going in my hooch.
DO use products labeled Yeast Nutrients. These are generally comprised of Diammonium Phosphate and Dipotassium Phosphate. The better ones add more ingredients. Crosby and Baker makes a product called Fermax that adds Magnesium Sulfate (yeast need Mg), and autolyzed yeast (yeast are apparently happily cannibalistic). Im using this Fermax product now for all raw grain mashes. You can get 2 lbs from ebay for $20 US, free shipping.
DO be careful with your water. Yeast hate salt (water softeners) and Iron (unsoftened hard water). So if youre screwed with bad water, as I am , suck it up and buy water or put in an RO and resupplement the water with minerals. Calcium Sulfate, Calcium Carbonate and Epsom salt (for Mg) will put the right minerals back in distilled or RO water.
Anyway, hope that helps. Curious others observations and solutions to this problem?
Cheers,
Jimbo