Decoction Mash: Piece of cake? or PITA?

[Ivan Lendl]

If i were to do a decoction mash with 10 lbs. of grain and i used 2 lbs. per gallon mash water,(5 gallons) say i did an initial dough in @ 95, how much of a decoction do i take out and boil to raise the temp to 122? and again to raise to 150? and finally 168?

is this the gist of it? just take out enough to boil for 20 min. then return to the mash and rest for 15 minutes, and repeat?

im thinking the hard part is getting the right amount out to boil and raise to proper temps by replacing.

is there a generalized rule of thumb for amounts to boil (decoctions)or just trial and error?

 

[Dude]

What kind of beer are you considering doing?

Except for a few specific styles a decoction mash is pointless with the well modified grains we use now. I can name only 2 maltsers that wouldn't be modified enough to warrant a decoction, and both of those malts are pilsner malts.

Just curious why you think you'd need it unless you are doing some kind of specific style, like a bock or a marzen style.

 

[Janx]

I don't do them often at all, but I've been playing with a Belgian Turbid mash, which is the same idea.

I use software (ProMash, SUDS, etc) to calculate the steps just like you would an infusion mash with infusions of boiling water. That will tell you the volume to pull off. Pull off liquid and some grains. Boil. Add back. Repeat.

It can be a bit of a PITA because grains can scorch easily. In any event, the mash will take you a bit longer

Have fun. Cheers

 

[Ivan Lendl]

i know i dont HAVE to do decoc. but i WANT to...a couple of reasons, mainly for sh*ts and giggles, but also cuz i plan on doing alot of bocks, marzens, and belgians, (or at least one of each if not alot) for the summer. I read an interview recently with some pro brewer and she was saying although malts these days are highly modified, they still do benefit from a triple-d. Beers did benefit more back in the day, but some feel they still do benefit, and the main reasons people (germans) went to step/infusion was to reduce time, and/or monies.


so i guess the only question i have is that if i start out with 5 gallons, im guessing ill lose maybe 1/2-3/4 gallons, and if i sparge with 2.5 gallons, ill have a pre-boil of 7 gallons. Does this sound right?

 

[RichBrewer]

Can some one tell me why a decoction mash doesn't leach tannins into the wort? Experts say to never sparge above 70° because that hot of water will release tannins into the beer.
Thanks!

 

[david_42]

There are some distinct flavors that a decoction will create in addition to adding body and mouthfeel. Plan on about 1/3 of the grain per decoction. The real trick is to transfer as little of the wort as possible when withdrawing grains for boiling, otherwise you'll destroy too many of the conversion enzymes.

 

[david_42]

A decoction doesn't leach many tannins because there is very little water in the grain being boiled, so the pH stays in the proper range.

 

[Ivan Lendl]

the march/april byo "help me mr wizard" tries to answer this same question...its too involved for me to explain, but it makes sense...but then a retired brewmaster from anheiser busch said that the tannins provide a certain 'brisk' flavor which is a hallmark attribute of decocted beers.

 

[Lou]

Can some one tell me why a decoction mash doesn't leach tannins into the wort? Experts say to never sparge above 70° because that hot of water will release tannins into the beer.
Thanks!

here's mr. wizard's kinda half-assed answer....
http://byo.com/mrwizard/1461.html

 

[Kaiser]

Decoction mashes do have their benefits if you want to do step mashed with a cooler set-up. They can even be used w/o a protein rest, if you mash in at 63C for a maltose rest and want to step up to a saccrification rest at 71C and then mash-out at 75C. In order to calculate the decoction volume, use this formula (or a program like BeerSmith)

T_end * (V_total) = T_start * (V_end -V_decoct) + 100C * V_decoct

V_decoct = V_total * (T_end - T_start)/(100 - T_start)

You can replace the 100 with 212 for F calculations.

I suggets drawing about 20% more than you calculate to compensate for evaporation loss, slow cooling of the main mash and other factors. Just don't dump everything back at once keep some in the kettle mix the mash and chek it's temp.

I will have to do some research about the tannin thing since I so far assumed that it won't be a problem.

Kai

 

[Ivan Lendl]

cool thanks for the info...i cant afford any programs right now, ill just fart around and do some research and use this formula...

 

[Ivan Lendl]

how do you get the decoc. out of the mash? with a ladel? do you just put it in a 2 qt pryex measuring cup?

i know your supposed to take out the thickest part, but im thinking its gonna be a pretty thin mash over all, do you just take enough grain/water to be able to stir like dave miller suggests?

 

[RichBrewer]

here's mr. wizard's kinda half-assed answer....
http://byo.com/mrwizard/1461.html

So it's the PH along with the temp that can extract tannins.
I think I better go get a degree in bio chemistry!

 

[Kaiser]

how do you get the decoc. out of the mash? with a ladel? do you just put it in a 2 qt pryex measuring cup?

i know your supposed to take out the thickest part, but im thinking its gonna be a pretty thin mash over all, do you just take enough grain/water to be able to stir like dave miller suggests?

I do my decoctions with about 1.3 qts/lb and ladle them out with a small sauce pan. As you noted, you want to get the tick part. You should know that most of the enzymes have been washed into the liquid and will not be deactivated during the boil since most of the liquid is left behind.

You need to get your decoction volume. If you don't have enough grains for the decoction volume (due to a thin mash), you may need to pull more liquid as well.


BTW, double check the formula. I couldn't find it on-line, so I did it in my head.

Kai

 

[Baron von BeeGee]

Here is a really good decoction primer/tutorial:
http://www.strandbrewers.org/techinfo/decoct1.htm

Part II gets into the nitty gritty details.

 

[AdIn]

From my experience I was trying to follow the article listed by BeGee and it's pretty easy. First I think 2lb per 5 gallons is too much water, usually you would want closer to 1.3 - 1.5 quart per pound. Then if you want to go from protein rest (122F) to around 152F you just take ~40% of your thick mash. You can always adjust your temp by quickly boiling small part of mash to bring it up a few degrees.