Fermentability of Grains

Hi all,

I understand that different grains will contribute a different ratio of fermentable to non-fermentable sugars, from the very fermentable (base malts) to the mostly unfermentable (darker specialty malts.) Is there any way to estimate the fermentable/unfermentable contributions of different grains? It would seem like very useful information for developing recipes, but I've never seen it listed anywhere.

Thanks,

TD

Its called PPG (points per pound per gallon). It's how much each grain will add to your gravity. Just about every vendor that you buy from lists the PPG fo the grain, and its the fundamental unit used for predicted gravity when making a recipe.

VTBrewer said:

Its called PPG (points per pound per gallon). It's how much each grain will add to your gravity. Just about every vendor that you buy from lists the PPG fo the grain, and its the fundamental unit used for predicted gravity when making a recipe.

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Thanks for the reply, but that's not what I'm looking for. PPG gives the extract potential of all sugars, it doesn't tell us anything about how much of the sugar is fermentable. Sorry if my question was unclear.

Depends too much on enzymatic conditions during the mash. You can very easily change the fermemtability of the sugars by just mashing a few degrees higher/lower.

You can get a good idea by comparing the steeping PPG to the mashing PPG. Starches don't dissolve very well.

Bump.....

This is a question that I've tried to get answered for the longest. Who knows - maybe something has changed since 2009! Of course the one reply about mash temps is valid, however there is bound to be a standard that is used, like with PPG and yield%.

I did a post on this recently. Most grains all ferment the same whether it is base malt, crystal or dark roast. What will effect the fermentability of the wort is lactose or sucrose.

http://woodlandbrew.blogspot.com/2012/12/final-gravity-in-recipe-formulation.html

WoodlandBrew said:

I did a post on this recently. Most grains all ferment the same whether it is base malt, crystal or dark roast. What will effect the fermentability of the wort is lactose or sucrose.

http://woodlandbrew.blogspot.com/2012/12/final-gravity-in-recipe-formulation.html

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Thanks, and nice write up! Admittedly it was when trying to add lactose to a recipe in BeerSmith that got me wondering since it simply adds it as a standard fermentable grain. I knew that lactose is "mostly" unfermentable as described in the chart you linked (I use the same one) , but still wonder about the specifics. In the same ilk, I would have to say that a crystal 120 has more unfermentables than 2 row base malt, but how much...? In each case, I fully agree that it's not enough to matter, but the anal-itical side wonders it the info exists somewhere. Oh well, in the mean time I think I'll RAHAHB..........

There was a thread about it on HBT here. Excel charts and everything. I also have a post on my blog about it back in October I think. Bottom line, it's not going to change your fg by even one point, so all the other processes variation effects it much more than the fermentability of the crystal.

Sounds good, although I do like a good Excel spreadsheet occasionally.

Thanks for the help and insight!

WoodlandBrew said:

There was a thread about it on HBT here. Excel charts and everything. I also have a post on my blog about it back in October I think. Bottom line, it's not going to change your fg by even one point, so all the other processes variation effects it much more than the fermentability of the crystal.

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Do you have proof of that somewhere? The crystal thread I saw from Nilo did show a marked difference in attenuation for, for example, Crystal 120. Perhaps I'm not remembering correctly.

Greg Doss presented on this (in part) at NHC. You can download the audio and slides here. In short, he was working on a multivariable model of fermentability that included grist, mash temp, mash length, yeast strain, and maybe also fermentation temp.

As one example, apparent attenuation for pilsner malt and C120 were 83.02% and 80.95%, respectively. (Mashed at 151F for 60min.)

afr0byte said:

Do you have proof of that somewhere? The crystal thread I saw from Nilo did show a marked difference in attenuation for, for example, Crystal 120. Perhaps I'm not remembering correctly.

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Thanks for brining this up. I haven't worked through the numbers in a while. My "it's not going to change your fg by even one point" was off the cuff. I should have said "it hasn't changed my fg by even one point"

I have not preformed these experiments myself, so I'm going off what Nilo posted. I agree that there is a difference, but I don't see it as significant in most cases.

Average attenuation from Nilo's data:
80 % for 2-row
77% for 50% C10, 50% 2-row
70% for 50% C40, 50% 2-row
67% for 50% C120, 50% 2-row

If we assume that the 2-row ferments the same regardless of being mashed with the crystal the 100% crystal fermentability numbers can be derived:

74% for C10
60% for C40
54% for C120

We can use these 100% values to then extrapolated a typical 10% w/w use of crystal the fermentability:

79% for 10% C10
78% for 10% C40
77% for 10% C120.

With the grain bill composed of 10% C120 the fermentability is 3% lower than 100% 2-row. If you started at an OG of 1.060 the FG would be 1.012 if crystal is assumed as equally fermentable to 2-row, and the FG would be 1.014. The difference in ABV is 6.5% vs 6.0%.

Here is Nilo's thread: (post number 108 has the data)
https://www.homebrewtalk.com/f128/testing-fermentability-crystal-malt-208361/index11.html