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Old 08-25-2009, 02:17 AM   #1
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Default Step Mash Conversion

I hope this is a technical enough question for this forum. I'm probably looking for the 75% uber technical answer, but feel free to chuck as much chemistry at this as you wish.

Background: I made a Saison the other day (recipe below).
- I did a rest @ 110F (0.75 qt/lb) then raised to 146F (1.5 qt/lb) for 60 minutes.
- I intended to mash out @ 165F but A) realized I was going to be low and B) had an idea.
- I increased to 155F via step infusion + small decoction and immediately took a gravity reading from the mash (1.060).
- I held @ 155F for 10-15 minutes, then took another gravity reading (1.066).

So it would appear to me that I made 6 pts worth of sugar that is primarily dextrines from alpha-amylase. This may have been in contrast to my goal of making a dry Saison.

I am assuming that the increase in gravity was due to some additional starch/sugar conversion. But after a 60 minute rest, I would think any available starch would have been converted. (I did not due an iodine test for conversion.)

- Is there some limit to how much carbohydrate beta-amylase can convert?
- Does beta amylase just act very slowly, and I would have gotten that same increase in sugar conversion by waiting another 20 minutes at my 146F rest?
- Or, would I basically always get that little gravity boost anyway since I'm going to increase to a mashout temp anyway? Unless I boost extremely quickly to 168 to stop all enzyme activity?

Thanks in advance for any feedback.

8# Belgian Pils
4# Flaked Spelt
1# Caravienne*
0.5# Aromatic

*I also realize that you could argue that my use of Caravienne is in contrast to my goal of a dry beer, but I had really nice success using 1# in a tripel w/ the Unibroue strain.
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