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Old 11-27-2010, 05:04 PM   #11
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I've been researching this very topic the last few days in an attempt to write my own brewing spreadsheet, and agree with you that the software all seems to blindly apply attenuation calculations to the extract potential, regardless of whether the extracted "stuff" is fermentable or not.

I am coming to believe that this is because there seems to be very little information out there on the subject. I did find a reference to this paper:

http://www.scientificsocieties.org/j...5-0330-275.pdf

which seems to indicate that extract of darker malts, including crystal types, is generally close to 0% fermentable. This does not seem like common knowledge among homebrewers, unless I am a complete n00b (possible!) and it is so obvious that it remains unsaid.

It also seems uncertain whether mashing these grains actually does anything. You would certainly need some grains with diastatic power in your mash, though.

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Old 11-27-2010, 05:21 PM   #12
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I was re-reading Palmer (Chapt 12) and wonder if this doesn't provide some more insight.

http://www.howtobrew.com/section2/chapter12-3.html

Doesn't your PPG get at your fermentability - with the assumption that all of the "sugar" you get will ferment 100%?

So, if your total PPG of sugar is 46, and the labs say light crystal has a max yield of 75% (for example), meaning a max PPG of 35, wouldn't that mean the remaining 25% are unfermentables?

http://www.howtobrew.com/section2/chapter12-4-1.html

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Old 11-27-2010, 05:41 PM   #13
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That was one of the first pages that I looked at. However, it is plain that those PPG numbers are the ones used by all software tools to compute OG, and therefore must include both fermentable and unfermentable sugars/dextrines.

For example, "everybody knows" that Carapils is almost entirely unfermentable. Yet the PPG is 32. Those points must go directly to FG (yield notwithstanding).

Sorry for a slight detour here, but there are numerous threads complaining of high FG on extract brews; but with a standard recipe with 7 lbs DME, and 1.5 lbs carapils and crystal, if you do the math assuming 75% real attenuation and that the specialty grain is unfermentable, you can compute an FG of around 1.020, which is exactly the "extract barrier" commonly seen and much lamented.

LATER:
Getting back to the OP, I wonder if the above implies that including the crystal in the mash does increase fermentability somewhat. It could still only get you a point or two though.

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Old 11-27-2010, 05:50 PM   #14
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Originally Posted by SeanRRogers View Post
That was one of the first pages that I looked at. However, it is plain that those PPG numbers are the ones used by all software tools to compute OG, and therefore must include both fermentable and unfermentable sugars/dextrines.

For example, "everybody knows" that Carapils is almost entirely unfermentable. Yet the PPG is 32. Those points must go directly to FG (yield notwithstanding).
I would assume that software would add the PPG of cara to the OG, but would not deduct much, if anything from the FG. Again, I don't use software, so I should just probably go away now

EDIT: I use beercalculus.com a little just to work on target OG....

And yes, I put in 10lbs of Cara and it says OG 1.048 and FG 1.012
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Old 11-27-2010, 06:03 PM   #15
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"which seems to indicate that extract of darker malts, including crystal types, is generally close to 0% fermentable"

I agree 100%. In fact, in my brewing tool, I set these grains to 0% fermentable, so all points goes straight to FG.

"It also seems uncertain whether mashing these grains actually does anything. You would certainly need some grains with diastatic power in your mash, though."

I recently learned from this forum that beta amylase can actually convert the long sugars (at some level) to shorter chains that become then fermentable, so I think that if you mash a crystal malt with another malt with diastatic power, it will affect the fermentability of the points coming from the crystal.

"Sorry for a slight detour here, but there are numerous threads complaining of high FG on extract brews; but with a standard recipe with 7 lbs DME, and 1.5 lbs carapils and crystal, if you do the math assuming 75% real attenuation and that the specialty grain is unfermentable, you can compute an FG of around 1.020, which is exactly the "extract barrier" commonly seen and much lamented."

Absolutely! I have seen many and many complains about high FG, some from extract recipes, some from AG, but many I believe are right on target. The problem is that the tool been used to predict FG is wrong, giving a false expectation of a lower FG, as we said, assuming that everything will be fermented.

At last, the way I calculate PPG is by using 2 key indicators from the spec sheets of each grain, the DBCG(dry basis coarse grind) and the MC%(moisture content). Using the formula PPG=46.214*(DBCG/100 - MC%/100 - 0.002). This has proven more accurate than just use what is out there on the database of the brewing tools like beertools or beersmith, etc.
This PPG is the max, assuming 100% mashing efficiency ( or steeping extraction?), so I aply the mashing efficiency on top of that. Now, which part of these points are actually fermentables, that is the golden question that I'm trying to answer with this experiment.

I'm starting my first test batch in few minutes. Wish me luck :-)
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Old 11-27-2010, 06:07 PM   #16
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Cool . Send the result to basic brewing radio. He will be imterested

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Old 11-27-2010, 06:18 PM   #17
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Quote:
I'm starting my first test batch in few minutes. Wish me luck :-)
Are you including some base malt in the mash, or are you doing it with crystal only first?

Cheers for actually doing an experiment!
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Old 11-27-2010, 06:20 PM   #18
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Cheers for actually doing an experiment!
speaking of, I need to dry hop my APA in my WLP001 v. AHS Greenbelt yeast experiment
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Old 11-27-2010, 06:26 PM   #19
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Just the crystal malt first, with 1/4# of rice rulls since I milled the crystal 3 times to get a better extraction.
This is how it looks

dsc06308.jpg   dsc06309.jpg   dsc06312.jpg  
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Old 11-27-2010, 09:07 PM   #20
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I must say that because there are so many variables that contribute to attenuation and you are just trying to look at how Crystal malt affects it, you may want to consider the following:

Mash at <149F to get the most fermentable wort
Mash for 90 minutes to really be sure conversion is compelte
Go with a no sparge to eliminate sparge variability
Over Oxeganate your worts
Over pitch


Another thought would be to do all the mashes in french presses at the same time and put them in a water bath to control the temp. That way, even if you were slightly off on temp, they would be the same.

You could do the following:

100% 6-row (control)
50% 6-Row + 50% Crystal 10L
50% 6-Row + 50% Crystal 40L
50% 6-Row + 50% Crystal 120L

The results could be calculated based on the difference between the test and control. OR you could pick one Crystal and just vary the percents (eg 5%, 20%, 50%). It may be that at lower levels (typical use), the affects it has on attenuation really isn't that great.

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