Going to brew up a rye IPA soon with about 20% malted rye. Is doing a beta glucan rest a good idea with that percentage? I was planning on throwing in about 8oz of rice hulls to help lautering. I use a continuous recirculation HERMS setup. If doing a rest is recommended should it be the entire mash or just the rye malt or does that matter? Also any recommendations on water to grist ratio? I usually go between 1.25 and 1.5 qts/lb but have not used this much rye before.
Personally, I would do a separate rest with the rye malt (as opposed to flaked rye) at 110 or so for just 10-15 minutes and add that back into the main mash a bit at a time. I would think of it as a low temp cereal mash.
I run a Brew Magic and that much rye without a protease rest could stick circulation a bit and cause lautering issues. With the separate mash you can be mashing the base at normal temps and slowly add in the rye mash without dramatically shifting your temperature rests. I don’t recall the mash temp to degrade protease, but if I recall, it happens quickly somewhere north of 130F. At least the circulation should help offset the temperature drop.
Best of both worlds then… and with a nice high temperature rest at mash out and the base mash not going through protease, you should avoid the potential of bad head retention.
That said - there are good arguments on either side.
So one idea would be to put all the brewing water in the mash tun, heat it up to 115 or so, add the rye malt and hold around 110 for 30min. While the rest proceeds i would heat up the HLT water further then being the recirc after 30 min. Increase temp up to my sacc rest (or slightly above), add the rest of the grain and fine tune the mash temp to hit goal. Would doing a Beta glucan rest with all the brewing water and only the 3-4lbs of rye malt cause problems?
It is absolutely not necessary based on my experience. I’ve done dozens of mashes with rye malt without a beta glucan rest. I’ve done a few with it…no difference. I have also never needed hulls. This is with % of rye malt from 20-60. I typically use about 1.63 qt./lb. for any mash.
Four out of the last five beers I made used 20% rye malt. I did not do any extra rests and did not have any issues lautering. I use 1.5 quarts per gallon and rest at 148 slowly ramping up to 170F on an old modified Brew Magic system.