A simple rye-mash recipe consists of 5 parts rye-mash and 3 parts corn. Other cereal grains such as wheat can be used in place of corn, but rye distillers are more likely to go with straight rye rather than recipes calling for other grains. In fact, some rye distillers insist on 100% rye, including malt. The use rye malt instead of barley malt so that the mash is comprised entirely of rye.
Rye malt is available at homebrew shops as a specialty malt, and it has a very high diastatic enzyme count that’s similar to that of 6-row barley malt, so rye malt is very well suited to making whiskey mash in general and is worth experimenting with for other recipes as well as 100% rye whiskey.
Rye has an interesting property to is in that straight un-malted rye grain contains alpha-amylase enzymes. Theses are the enzymes that “liquefy” mash. The liquefaction phase of the mash cycle is the phase where the long-chain insoluble starches, which make the mash thick lie a porridge, are reduced to short-chain soluble starches, hence liquefying the mash. These enzymes can be activated by a mash rest between 149-158 degrees F.
It can be somewhat difficult to take advantage of these enzymes. However, there should be enough enzymes in the grain to do the mash conversion. If you are mashing flacked rye then the initial rest at 155 F, after the flacked rye is added to the 165 F mash water, will effect a liquefaction rest during the period before the malt is added. This rest is not at all important to the mash cycle, but it does give the malt enzymes a good head start.
If you re mashing non-flacked rye such as rye flour or rye meal, which requires infustion into the mash water at near boiling temperatures and then a rest for 10 or 15 minutes to disperse the starches, them this liquefaction rest becomes impractical. The near boiling temperatures would denature the enzymes, so they would not be active by the time the mash cooled to 155 F. However, commercial distilleries do take advantage of these enzymes when mashing rye because they can actually reduce the over-all amount of energy used in the process.
In order to use these enzymes when mashing none-flacked rye they have to employ a step-mash regimen rather than doing a straight infusion mash. To do a step-mash procedure, the grain must be added to 165 F mash water for 10 to 15 minutes and then resting at 155 F until the mash liquefies.
The mash is then either chilled or left to cool to 152 degrees F and the malt is added. The process is the same as for the other methods from here on.
It’s unlikely that a home operation would realize any energy savings by employing this method, and it would certainly be a lot more trouble and time consuming than doing a straight infusion mash. So, it’s recommended that if you’re mashing non-flacked rye that you ignore the indigenous alpha-amylase enzymes in the rye and conduct the mash cycle in the same manner as with any other grain.