Author Topic: surprisingly low wort fermentability  (Read 3363 times)

Online Kaiser

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surprisingly low wort fermentability
« on: September 08, 2012, 10:28:27 AM »
Last weekend I brewed a Hopfenweiss inspired Weissbier IPA. I was shooting for highly fermentable wort with 30 min rests at 150, 144 and 150 F. When I got back the FFT results I was very surprised that i got only 75 % apparent attenuation.

I'm not sure what happened here. Maybe the Pils and wheat malt didn't have enough diastatic power?

But this was a good opportunity to start an experiment on diastatic enzymes during fermentation. So I put about 600 ml each of the beer into 1000 ml fasks. To one I added only water as the control to account for the lower OG that the others will have. To one I added some Beano and the last one received a 10 Plato wort extracted from malt with a 30 min mash at 140 F. This leaves most of the b-amylase intact and should kill proteinases and most of the bacteria.

This morning I saw quite some activity in the flask with the malt extract. There is also some activity in the Beano flask. I may have to add some some. I didn't know how much Beano is needed since brewers are generally advised against using it. Very little activity in the control fermentation.

Kai

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Re: surprisingly low wort fermentability
« Reply #1 on: September 09, 2012, 05:31:15 AM »
I don't know for sure, but the enzyme in beano may be denatured by alcohol. This happens to pectic enzyme which must be added before fermentation.
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Offline tom

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Re: surprisingly low wort fermentability
« Reply #2 on: September 09, 2012, 09:56:44 AM »
I have added Beano to an 8% beer and it went up to 12%.  Although I don't recommend it!   :o
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Re: surprisingly low wort fermentability
« Reply #3 on: September 09, 2012, 12:49:10 PM »
The beano seems to working. Just a bit slower.

Tom, how much beano did you and to how much beer?

Kai

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surprisingly low wort fermentability
« Reply #4 on: September 09, 2012, 01:08:15 PM »
Kai, you might also want to check out Greg Doss's presentation on fermentability from the Seattle NHC.  One thing I found interesting was that his experiment identified a mash temp of 153 as having the greatest attenuation.


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Offline mainebrewer

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Re: surprisingly low wort fermentability
« Reply #5 on: September 11, 2012, 05:00:56 AM »
When I was an extract brewer, occaisionally, fermentation would stall.
I found that 1/2 tsp per 5 gallons was enough to get the last few points that I wanted.
Never had issues with "bottle bombs".
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Online Kaiser

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Re: surprisingly low wort fermentability
« Reply #6 on: September 11, 2012, 05:35:28 AM »
Mainebrewer, the beano I have comes as capsules. Did yours come add a powder?

Kai

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Re: surprisingly low wort fermentability
« Reply #7 on: September 11, 2012, 07:43:27 AM »
I used beano once. it was the liquid kind. If I recall I added about 10-15 drops to 5 gallons of an imperial stout that would not go below 1.036 (extract batch) It worked and got down to 1.020 before i bottled because it seemed stable. about a month later the bottles started to break  :'(. the beano just keeps working slowly.
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Offline tom

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Re: surprisingly low wort fermentability
« Reply #8 on: September 11, 2012, 08:00:55 AM »
+1, mine was the drops too
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Re: surprisingly low wort fermentability
« Reply #9 on: September 11, 2012, 08:53:00 AM »
Last weekend I brewed a Hopfenweiss inspired Weissbier IPA. I was shooting for highly fermentable wort with 30 min rests at 150, 144 and 150 F. When I got back the FFT results I was very surprised that i got only 75 % apparent attenuation.


I've never seen a mash schedule where the temp is lowered.  Is your mash schedule right?  If yes then why go back down to 144?
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Re: surprisingly low wort fermentability
« Reply #10 on: September 11, 2012, 09:22:44 AM »
I've never seen a mash schedule where the temp is lowered.  Is your mash schedule right?  If yes then why go back down to 144?

That was a typo. the first rest was at 130 F (55 C).

There are mash schedules that lower the temp. But for these to work you have to add fresh malt.

Kai

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Re: surprisingly low wort fermentability
« Reply #11 on: September 11, 2012, 09:49:18 AM »
Kai, you might also want to check out Greg Doss's presentation on fermentability from the Seattle NHC.  One thing I found interesting was that his experiment identified a mash temp of 153 as having the greatest attenuation.


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I'm thinking that your last rest should have been in the alpha-amylase temp range (154-162 per http://www.howtobrew.com/section3/chapter14-1.html), which is in line with Greg Doss's presentation re single infusion mashes.
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Online Kaiser

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Re: surprisingly low wort fermentability
« Reply #12 on: September 16, 2012, 06:38:17 PM »
Quote
I'm thinking that your last rest should have been in the alpha-amylase temp range (154-162 per http://www.howtobrew.com/section3/chapter14-1.html), which is in line with Greg Doss's presentation re single infusion mashes.

I did hold a 45 min rest at 161 F as well. I did not mention it since it was not a rest for fermentability.

I think the mash schedule I used was fine. The optimum numbers you have are for single infusion rests. With step mashes the mechanics are a bit different and one can get even better fermentability though rests are lower temps before the mash is brought to the higher temps.

I finally tasted uncarbonated samples of the beers and wrote about it on my blog: http://braukaiser.com/blog/blog/2012/09/16/enzymes-in-the-fermenter/

Excerpt:
I also got an opportunity to measure the current extract and pH. Most importantly I was able to taste uncarbonated samples. Here are the stats:

--(I don't know how to do tables in posts. This layout is messed up) ---
control   malt extract   Beano   
corrected starting extract   17.8   17.7   17.7   Plato
days fermented   9   9   9   days
Final extract   4.3   2.5   2.2   Plato
ADF   75.9%   85.9%   87.6%   
pH   4.48   4.4   4.35   

As expected the addition of enzymes boosted attenuation. Beano seems to digest more dextins than a malt extract. I wonder to what extent the difference is caused by limit dextrins (1-6 glucose links), which can only be broken by limit dextrinase, an enzyme which likely did not survive the 30 min mash at 60 C. Beano’s glucoamylase is likely able to cleave both the 1-4 and the 1-6 links found in starch leaving only glucose and no limit dextrins.

It was surprising, however, that even with enzyme use during fermentation the apparent attenuation stayed in the mid 80′s. This suggests that the low wort fermentability may not have been the result of incomplete starch and dextrin break-down during the mash. After all, I was going for very fermentable wort and held 30 min rests at 55 C, 63 C and 65 C followed by a 45 min rest at 72 C. I was expecting to get an attenuation limit in the high 80′s with this mash schedule.

So much for the metrics, here are some brief tasting notes:

control: No noticeable off flavors. While this was a Weissbier yeast, it is a yeast that produces only limited amounts of phenolics. The mouthfeel is rather thick and the beer does not have the refreshing IPA character that I was going for

enzymatic malt extract: No off flavors. Whatever surviving microbes came in from the malt did not take hold and spoil the beer. I’ll have to see how this develops as the beer sits in the bottle for a month. The mouthfeel was much lighter and more  easy drinking than the control. This was the taste I was shooting for.

Beano: No off flavors either. The mouthfeel was even lighter than the malt extract version. But it was not the dreaded “rocket fuel” that others have gotten from Beano before. I think this version felt a bit too thin in its taste, though. I’ll have to defer to tasting a carbonated sample.

Offline denny

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Re: surprisingly low wort fermentability
« Reply #13 on: September 17, 2012, 11:28:25 AM »
Interesting info as always, Kai.  Sorry about the wild goose chase with Greg's info.  I had totally forgotten that is was for single infusion mashes.  I plead old age!
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Online Kaiser

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Re: surprisingly low wort fermentability
« Reply #14 on: September 17, 2012, 06:05:52 PM »
Denny,

Actually, even for single infusion mashes the optimum temp for best attenuation depends on the mash time as well. The longer the mash time the lower the optimum temp will be.

Now that I did not spoil my beer by adding unboiled wort, I'm actually excited using this technique to brew a DIPA or some other higher gravity beer that could benefit from high attenuation w/o adding sugar.

BTW, looks like the avatars are broken again.

Kai