Two mashes or reiterated mash?

[jerrylotto]

I usually do the first mash with all base malt and save the specialty grains for the second iteration. Also, I use clear water to sparge both times - I use the wort from the first batch as strike for the second. It has always worked well for me and you want a larger volume for a 120 min boil anyway (which is what I typically use for the my high sugar worts).

 

[bwible]

I use a braumeister, so quite limited by grain capacity. I double mash about twice a year and have no problems doing it the way I’ve described. If target OG is missed I add brewing sugar.

I have an Anvil Foundry 6.5. It holds 8 lbs of grain. I use it for 3 gallon batches. Only so much you can do with 8 lbs of grain. Less than 4 kilos for you guys? Works well for average strength stuff.

 

[Mac's Brew]

When I brew big beers (barleywine and Imperial stout) I divide evenly to have approximately 50% of each grain in both of the two step mashes (140° F/158° F). I sparge both, collecting 50% of my wort from the first. I use extra hot liquor (at 158°) when sparging the first batch and collect the extra wort to use with the strike water in the second mash. At the end I raise the second mash to 170° and sparge with 170° clear water. To make it easy, I use 5.2 pH stabilizer in both mashes.

I usually add some DME and some dextrose to the kettle to boost the gravity. My last one (October 2021) was an English style Imperial Oatmeal Stout. 140 lbs of grain (1bbl batch, 90 minute boil), OG 1.108 FG 1.036. The first runnings of the second mash were 10 points higher than the first mash.

Since high efficiency is hard to attain with these big beers, I think a reiterated mash is a good way to increase efficiency, and I always split/mill each grain 50/50. Even so, I still have to add some DME (yes it's expensive) and limited amounts of dextrose (pretty cheap) to get close to my targets.

 

[doug293cz]

When I brew big beers (barleywine and Imperial stout) I divide evenly to have approximately 50% of each grain in both of the two step mashes (140° F/158° F). I sparge both, collecting 50% of my wort from the first. I use extra hot liquor (at 158°) when sparging the first batch and collect the extra wort to use with the strike water in the second mash. At the end I raise the second mash to 170° and sparge with 170° clear water. To make it easy, I use 5.2 pH stabilizer in both mashes.

I usually add some DME and some dextrose to the kettle to boost the gravity. My last one (October 2021) was an English style Imperial Oatmeal Stout. 140 lbs of grain (1bbl batch, 90 minute boil), OG 1.108 FG 1.036. The first runnings of the second mash were 10 points higher than the first mash.

Since high efficiency is hard to attain with these big beers, I think a reiterated mash is a good way to increase efficiency, and I always split/mill each grain 50/50. Even so, I still have to add some DME (yes it's expensive) and limited amounts of dextrose (pretty cheap) to get close to my targets.

The simulations I did for batch sparging showed that a single large mash had a slightly better lauter efficiency than an iterated mash. If you have the mash volume, go single step. If you can't get all the grain into your mash vessel at once, than go ahead and iterate - the efficiency penalty is small.

Brew on