by Hill » Thu Mar 07, 2013 1:46 pm
I haven't had a go with any grain spirits yet but have over 200 full mash brews under my belt, in regards to what i know between 60 and 70 deg most of your main conversion will happen the lower the mash temp ie 62 deg, the more fermentables and lower the end gravity, mashing higher ie 68 deg lessens the fermentables and ends in having a higher end gravity which would usually would give more body in a beer. Out side that range you would get different types of conversions ie 40-50 deg is an acid rest which would lower your PH, 50 - 60deg is a protein rest to break down proteins in the mash. I'm reading from harvest to moonshine at the moment which has all types of rests and i can tell you from all the research iv done and experience i have it would make a difference but if you can't get your times and temps exact and you have limited equipment you may not get out anything for the effort you have put in and I don't know how much you would notice the difference once distilled.
If it was me with basic BiAB equipment with limited ability to raise and drop mash temps id boil my starting water to remove chlorine, mash 65deg, Id add a teaspoon of calcium sulphate to lower the PH and at about 60 mins i do a conversion test by putting some wort on a plate and adding a drop of iodine, if the drop disperses quickly or stays dark it would mean it isn't finished conversion and it would need longer.
This wold give you a starting point then you could raise or lower the mash temp based on if you wanted/needed a sweeter or dryer mash.
There's programs out there that help you calculate all your variables, I use Beersmith that has a free 30 day trial but there are others, these will tell you what all your numbers are.
I hope all that makes sense.