Decoction mashing with a one gallon BIAB batch. Possible?

[MMBB]

I want to try and brew a Czech Pilsner recipe and it requires a triple decoction mash. Not having brewed this recipe, or done any decoction mashing, before I'd like to try a small batch on top of the stove before going full on with a five gallon brew day.

Is it possible to do a decoction mash with BIAB? I would assume that I'd just dump the grain bag into another kettle, do the decoction, transfer it back, and repeat as necessary. Would I be better off trying this with a two gallon batch? I don't have enough kettle capacity for a three gallon batch.

 

[SanPancho]

you can totally do it. just do the math, or find a calculator to get your volumes figured out. i used to know where to find one of those online but i dont recall anymore. maybe beersmith or one of those has it? someone here on the forum can do the calcs for you?

id assume if you're doing a 1 gal batch you're starting with about 2 gals of full volume mash water. that should be enough to pull off enough to decoct, and leave enough in kettle for the mash to keep going.

 

[dmtaylor]

I just did a 1.3-gallon decoction two weeks ago. Turned out great. Nice thing about decoctions with small batches... it's a piece of cake and takes about the same time as a regular batch too.

 

[SanPancho]

I just did a 1.3-gallon decoction two weeks ago. Turned out great. Nice thing about decoctions with small batches... it's a piece of cake and takes about the same time as a regular batch too.

did you use a calculator for the boil sizes?

 

[dmtaylor]

did you use a calculator for the boil sizes?

I did not use software or whatever. I did manual calculations. My method is a double-decoction, loosely based on Hockhurz but skipping some steps that I feel are not necessary for success, particularly the protein rest phase. Here, I'll pull up my notes.....

Oh crap, I didn't keep my notes. But I can kind of redo the math right now without much trouble.....

Mashed in with about 1.7 qt/lb room temperature water, so with about 80% brewhouse efficiency and only 2.25 lb malt, that was about 1 gallon. Then after mixing well, immediately removed most of the grains and part of the liquid using a colander for the first decoction. Brought that up to about 153 F for 15 minutes. Then added an extra pint of water to account for evaporation, brought to the boil for about 20 minutes or so. Finally brought that back to the main mash shooting for anywhere around the same 153 F. First decoction done and resting there now in the 150s for another 15 minutes. Then pulled much of the liquid from the main mash and brought that to a boil. Soon as it boils, add back to the main mash for mashout in the mid 160s (I never am able to hit 170 F, probably need to extract almost all the liquid and a little grain to get there). Once all that is done, dump into a bag if it's not in one already, pull the bag, do a dunk sparge for efficiency or otherwise add another 1.5 gallons water for the proper volume, bring to the boil then continue brewing as normal.

This entire decoction process only takes about an hour with a little batch like ours, not the laborious 3-hour ordeal of some bigger decoctions.

 

[MMBB]

Thanks dmtaylor! Why did you decide that the protein rest wasn't required for that brew?

 

[TexasWine]

I want to try and brew a Czech Pilsner recipe and it requires a triple decoction mash. Not having brewed this recipe, or done any decoction mashing, before I'd like to try a small batch on top of the stove before going full on with a five gallon brew day.

Is it possible to do a decoction mash with BIAB? I would assume that I'd just dump the grain bag into another kettle, do the decoction, transfer it back, and repeat as necessary. Would I be better off trying this with a two gallon batch? I don't have enough kettle capacity for a three gallon batch.

You might know this, but the necessity of decoction mashes has been a topic of debate. If you haven't done it already, I'd recommend some reading before going through with one.

 

[MMBB]

You might know this, but the necessity of decoction mashes has been a topic of debate. If you haven't done it already, I'd recommend some reading before going through with one.

I did browse through a post a little bit ago that put forth the theory that doing a step mash in lieu of a decoction would produce the same result. I'll have to go back and do a little more reading. However, I'd like to try it the traditional way as well.

 

[dmtaylor]

Thanks dmtaylor! Why did you decide that the protein rest wasn't required for that brew?

Protein rests kill body and head retention. It's happened to me more than once, and has happened to multitudes of other people as well, I'm not the only one. The reason is that malts in the 21st century are so well modified that you can't even buy an undermodified malt anymore. I know because I've looked. People will tell you that this malt or that malt is "undermodified" based on what someone else told them, but if you actually look at the Kolbach index for the malt, it's just as well modified as any other malt so they're wrong. I don't do the protein rest because our malts are just too good now and it hurts the body of the beer. So skip it. Don't ever do a protein rest again unless malting your own grains from scratch!!!!!!!

 

[SanPancho]

I did browse through a post a little bit ago that put forth the theory that doing a step mash in lieu of a decoction would produce the same result. I'll have to go back and do a little more reading. However, I'd like to try it the traditional way as well.

no, it wont. while the decoction may have initially been used to perform the step mash, it has another function which is to cook those sugars at boiing temps which generates protein reactions that contribute flavor. kinda of like browning meat before you put it in a stew. so there are definitely still reasonss to do a decoction mash.

that said, , alot of folks use melanoidin malts which provide the same flavors, or at least that's what they claim. ive never used them so i couldnt say.