decoction question

I was reading a thread that said squeezing the grain bag would release tannins and make your beer astringent. What about decoction mashing? Does that release tannins? Has anyone ever had problems with off-flavours from a bad decoction mash?

Decocting beer is fine for technical reasons that I *believe* are mostly centered around mash PH. It's not JUST temperature that determines tannin extract.

My decoction problems are always attributed to swearing and temperature issues (not necessarily in that order). I don't know for sure but I always figured as the_bird said, it has to do with pH levels.

The pH of a decoction is not high enough to release excessive tannins, some are extracted but they usually don't go above the taste threshold.

Phew. That's good news.

I've done many decoctions, sometimes three times in a row for a pilsner. I've used decoctions to simulate a step mash, and I've used decoctions to rescue a low strike.

The only time I ever picked up astringency was when I badly over sparged, and that was a single infusion.

That's all anecdotal of course.

According to Jim Crute at Lightning Brewery who does almost exclusively decoction, it is only certain grains which may be prone to releasing astringency (ones he does not typically use).
On the grain bag squeezing thing, I think its a big myth. If you look at process scale mash filters that some of the big (very big) brewers use, they end up compacting the mash into a highly compressed filter cake and then force water through it. I asked Charlie Papazian about that at a recent event and agreed that is not true. He pointed out the Goat Scrotum ale recipe in the Joy of Homebrewing book that specifies squeezing the bag as a counter argument.

Germey said:

According to Jim Crute at Lightning Brewery who does almost exclusively decoction, it is only certain grains which may be prone to releasing astringency (ones he does not typically use).

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I read that Maris Otter malt is prone to releasing tannins, whereas modern barleys->malt have had that their tannin content reduced genetically (as in, cross-breeding). Anyone else hear this before?

GreenWolf said:

I read that Maris Otter malt is prone to releasing tannins, whereas modern barleys->malt have had that their tannin content reduced genetically (as in, cross-breeding). Anyone else hear this before?

Click to expand...

I have done Decoction mashes with MO twice and never had a problem. Key is to watch mash ph and to have full conversion before boiling.

when you do a decoction mash most things I read state you have to take about a third of the mash and taking the thickest part of the mash. Does that mean you have to leave most of the liquid behind? If so how do you get the grains to boil (and not scortch) if you take most of the liquid out of it? I've never done a decoction or known anyone personally that have done one. I'd love to see one done.

You take just enough liquid with you so that it's basically a thick porridge, just enough so that you CAN boil the grains. Just a wee bit of water above the mass of grain.

Resto3 said:

when you do a decoction mash most things I read state you have to take about a third of the mash and taking the thickest part of the mash. Does that mean you have to leave most of the liquid behind? If so how do you get the grains to boil (and not scortch) if you take most of the liquid out of it? I've never done a decoction or known anyone personally that have done one. I'd love to see one done.

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Decoction mashes are generally fairly thin mashes (about 2 qts/lb). when you then take the tick part, you end up with a decoction mash that is about 1.2 qts/lb. This is the mash consistency that many brewers use for their single infusion mashes, which should be thin enough to be easily stirred. Also, keep the flame low. You are aiming for a 2-4 *F/min rise of the mash. With this and the thinner decoction you don't have to stir all the time either.

Having this said, I just brewed a Doppelbock where I had to decoct a really thick mash as the amount of water that I can use in the mash is limited by the size of the mash tun. In my case a 5 gal cooler.

Kai

Germey said:

According to Jim Crute at Lightning Brewery who does almost exclusively decoction, it is only certain grains which may be prone to releasing astringency (ones he does not typically use).
On the grain bag squeezing thing, I think its a big myth. If you look at process scale mash filters that some of the big (very big) brewers use, they end up compacting the mash into a highly compressed filter cake and then force water through it. I asked Charlie Papazian about that at a recent event and agreed that is not true. He pointed out the Goat Scrotum ale recipe in the Joy of Homebrewing book that specifies squeezing the bag as a counter argument.

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Sorry couldn't avoid it.

Resto3. Here is a picture of my last Decoction.

Resto3 said:

when you do a decoction mash most things I read state you have to take about a third of the mash and taking the thickest part of the mash. Does that mean you have to leave most of the liquid behind? If so how do you get the grains to boil (and not scortch) if you take most of the liquid out of it? I've never done a decoction or known anyone personally that have done one. I'd love to see one done.

Click to expand...

Take everything I say with a bucket of salt, but I have found that adding a litre of water to the grain taken from a decoction does no harm. This will slow the boil, but it will *lubricate* the boil once it starts. You want the decoction to be as evenly heated as possible so that you can hit your temperature target when you add it back to the mash. If your just decocting for malt character and not temperature, then you only have one target and that is anything under 75c, and this should be done at the very end of the mash time.