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Old 06-24-2010, 04:43 PM   #1
Jul 2009
Chapel Hill, NC
Posts: 312
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Hey folks. I'm doing a double decoction for an Altbier right now, and I started to wonder how efficiency can be reasonably good. My thoughts: I'm boiling a decent portion of the grain and thereby denaturing the enzymes. About a third of the mash isn't there for most of the saccharification rest, so it seems like my efficiency should be pretty low. Is there a light-speed saccharification that takes place as the decoction is heated to boiling?

- E

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Old 06-24-2010, 04:50 PM   #2
Yuri_Rage's Avatar
Jul 2006
Posts: 14,290
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This is a pretty simple explanation:


Remember, there are lots of enzymes in highly modified malt, and they work fairly quickly.
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Old 06-25-2010, 03:15 AM   #3
Sep 2009
Atlanta, GA
Posts: 70

During mash in and/or your protein rest (in any case before you pull the first decoction) the majority of the enzymes have gone into solution, i.e. they're in the thin part of the mash. When you pull the thick part of the mash for the first boil, you'll of course bring some amylase enzymes into the the boil kettle, which will be denatured when you boil, but not to worry, the workhorse amylase is still in the mash tun safely waiting to be brought up to working temperature.

When I have done decoctions, during the boils before saccharification (in my case, the first boil), I follow Kaiser's instructions and do a mini-saccharification rest in the decoction kettle, just to make sure that during saccharification of the main mash there is the appropriate amount of enzyme to starch.

Point being, the enzymes in solution in the mash tun don't get boiled, so they're still able to catalyze their reactions, and truth be told, they are probably sufficient, given time, to convert all of the starch in the mash without the mini-saccharification rest.

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Old 06-25-2010, 10:24 PM   #4
malkore's Avatar
Jun 2007
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I've tested my single infusion mash at 30 minutes before and showed full conversion of Briess 2-row. Like Yuri says, in most of today's modern malts, there's way more enzymatic activity right out the gate than what our forefather brewers experienced.

I typically never mash more than 45 minutes before I vorlauf and start the batch sparge.
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