Author Topic: Fermentability  (Read 873 times)

Offline PeeBee

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Fermentability
« on: November 05, 2019, 10:12:43 AM »
For calculating starting gravity the program uses the ingredient's configured value for "potential extract" and the hardware's value for "brewhouse efficiency". Along with values such as mash temperature the program can then make a good stab at the starting gravity of the beer and the ABV of the finished beer.

For some ingredients (e.g. lactose) there is the option to declare it "not fermentable" so it still provides the calculations with a figure for "potential extract" to come up with a starting gravity, but none of that extract is involved in calculating alcohol so it all ends up in the estimate of finishing gravity.

Good! Following? Sorry, this is a bit long-winded.

But there is nothing in between. The calculated extract is either processed as fermentable, or else all deemed not fermentable.

The figure for "extract" can be manipulated to only reflect fermentable extract. But then any "not fermentable" extract is skipped and not included as part of the final gravity. This has become a problem for me when designing beers containing a lot of crystal malt (particularly low-alcohol, <0.5% ABV, beers) where quite a high proportion of the sugars can be "not fermentable" or convertable having been subject to caramellisation and "Maillard's Reaction". Most extreme is "dextrin malt" ("Carapils", "Carafoam", etc.) which undergoes processes to preserve the dextrins against attack by mash enzymes and yeast enzymes despite being very light in colour and not being subject to caramellisation.

Currently I'm electing to designate all crystal malt as "not fermentable" for these low-alcohol formulations, which isn't ideal.

So: Could we have an option for "not fermentable" that took a figure representing the degree of fermentability ratther than just a basic checkbox. So if the ingredient option had a value of 50%, half would be passed to the calculations that figure out how much alcohol it will produce, and half will be treated as "not fermentable".

Offline Brew Bama

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Re: Fermentability
« Reply #1 on: November 05, 2019, 11:53:41 AM »
You could add two separate entries : half ?non fermentable? and the other half ?fermentable? or other ratio variations.

Have you seen this? Testing fermentability of crystal malt (post 108)

BLUF:

A)Crystal malt have sugars but still hold starches that can be converted
B)The amount of sugars that one can extract from crystal malts would increase if mashed with a base malt since the starches will be converted. PPG showed to increase by about 20%, regardless of the kilning level of the crystal malt.
B)The sugars from crystal malts are VERY fermentable, contrary to what we knew. Fermentability will depend on multiple factors like:
-Steeping crystal malt alone will yield sugars that can be attenuated by 50% for crystal 10 and 40% for darker malts.
-Mashing crystal malts with base malts will yield sugars that are almost as fermentable as base malt itself. For the 50-50% rate used, sugars from crystal-10 malts were attenuated by 70% while crystal 40 and 120 by 52% minimums. For a 10% crystal to grist rate, I guess it could be treated just as a base malt, which means very fermentable.
« Last Edit: November 05, 2019, 12:22:08 PM by Brew Bama »

Offline PeeBee

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Re: Fermentability
« Reply #2 on: November 06, 2019, 02:45:42 AM »
Oh yes. I may not of seen that particular article, but that chap ("Nilo") has been fairly prolific with his "sugars from crystal malts are VERY fermentable". Highly commendable, but only the opinion of ONE person (in a big world). I'd need a bit more convincing than that! And there is this - https://byo.com/mr-wizard/dextrin-malts/. And my own experiences with "low-alcohol" beer where quite a high proportion of extract can be from crystal malt, but calculating how much of that might be fermentable isn't easy (crystal malt is good for "low-alcohol" beer because it includes bags of flavour and ALOT of unfermentable dextrin).

I'm not asking Beersmith to provide values for "fermentability", just asking for the ability to manipulate it one's self.

Offline BOB357

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Re: Fermentability
« Reply #3 on: November 06, 2019, 06:05:47 AM »
You could adjust the yield of individual crystal malts to match your findings.
Bob

Offline PeeBee

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Re: Fermentability
« Reply #4 on: November 06, 2019, 08:10:20 AM »
No you can't! I mentioned that in the OP: "The figure for "extract" can be manipulated ?" etc.

Offline brewfun

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Re: Fermentability
« Reply #5 on: November 06, 2019, 08:19:44 AM »
It's true that BeerSmith looks at fermentability as binary, but so does most of the brewing industry and homebrew advice.

The fermentability calculation is driven by the max attenuation number of your yeast.

The second important calculation is the mash temperature in the recipe and the slope defined in options. This is where you can fine tune fermentability for your overall techniques.

In my brewing practice, I usually mash for high fermentability, high extraction percentages and look for a lot of attenuation from my yeast. I tend to use less than 12% specialty malts and don't really have too much difference between predicted attenuation and actual.

Is this concern something your're seeing in actual practice?
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Offline BOB357

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Re: Fermentability
« Reply #6 on: November 06, 2019, 08:47:48 AM »
I reread your OP and now see your point.








Bob

Offline PeeBee

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Re: Fermentability
« Reply #7 on: November 06, 2019, 09:19:59 AM »
? Is this concern something your're seeing in actual practice?
It is!

Though perhaps I wouldn't have if I hadn't branched out into "low-alcohol" brewing. It's the opposite to your brewing practice; so low fermentability, therefore low (fermentable) extraction percentages, and low attenuation from yeast (I use "Fermentis S-33" to leave dextrin alone, but some are experimenting with weird "wild" yeast - saccharomycodes ludwigii, and that isn't a spelling mistake!). I might also use 30-50% crystal/caramel malts - a death knell for "normal" beers but when dealing with that much crystal malt the brewing software could help a lot by doing more to take "fermentability" into account.

Online Oginme

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Re: Fermentability
« Reply #8 on: November 06, 2019, 09:25:35 AM »
? Is this concern something your're seeing in actual practice?
It is!

Though perhaps I wouldn't have if I hadn't branched out into "low-alcohol" brewing. It's the opposite to your brewing practice; so low fermentability, therefore low (fermentable) extraction percentages, and low attenuation from yeast (I use "Fermentis S-33" to leave dextrin alone, but some are experimenting with weird "wild" yeast - saccharomycodes ludwigii, and that isn't a spelling mistake!). I might also use 30-50% crystal/caramel malts - a death knell for "normal" beers but when dealing with that much crystal malt the brewing software could help a lot by doing more to take "fermentability" into account.

Can you give us some specific examples of your mash temperature, OG and FG?  How well is the FG calculation coming out for you in higher alcohol recipes?  Just looking to see if there is another handle which can be used to get you where you want to be.

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Offline PeeBee

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Re: Fermentability
« Reply #9 on: November 06, 2019, 09:42:16 AM »
You could add two separate entries : half ?non fermentable? and the other half ?fermentable? or other ratio variations. -
I could; an entry for a "dummy" makeup ingredient that can be used to compensate for the fermentable proportion of (e.g. crystal) malt (which will still be "not fermentable" but with it's extract reduced to only cover the "not fermentable" bit).

Thanks for making me think along those lines. But it is still only a better work-around than I'm using and not a "fix".

Offline PeeBee

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Re: Fermentability
« Reply #10 on: November 06, 2019, 10:11:01 AM »
? Is this concern something your're seeing in actual practice?
It is!

Though perhaps I wouldn't have if I hadn't branched out into "low-alcohol" brewing. It's the opposite to your brewing practice; so low fermentability, therefore low (fermentable) extraction percentages, and low attenuation from yeast (I use "Fermentis S-33" to leave dextrin alone, but some are experimenting with weird "wild" yeast - saccharomycodes ludwigii, and that isn't a spelling mistake!). I might also use 30-50% crystal/caramel malts - a death knell for "normal" beers but when dealing with that much crystal malt the brewing software could help a lot by doing more to take "fermentability" into account.

Can you give us some specific examples of your mash temperature, OG and FG?  How well is the FG calculation coming out for you in higher alcohol recipes?  Just looking to see if there is another handle which can be used to get you where you want to be.
FG is coming out okay-ish for "normal" beers, and there is the option to dabble with the "slope of FG atten adjustment" option (although that option is always handicapped by trying to make a straight line approximate for a curved line).

But an earlier "low-alcohol" brew had an estimated FG 1.005, an actual FG 1.009, estimated attenuation 65%, actual 28%, and estimated ABV 1.3%, actual ABV 0.5%. Attached is the "Session" page. 50% base malts, 50% crystal malts.

EDIT: Missed some requested info. Predicted SG 1.015, actual 1.012 (I messed that one up a bit?). Mash temperature 74C !).
« Last Edit: November 06, 2019, 10:23:17 AM by PeeBee »

Offline brewfun

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Re: Fermentability
« Reply #11 on: November 06, 2019, 10:33:58 AM »
I might also use 30-50% crystal/caramel malts - a death knell for "normal" beers but when dealing with that much crystal malt the brewing software could help a lot by doing more to take "fermentability" into account.

I just looked at a 3 year old dark mild recipe that BeerSmith predicts at 2.6% abv. It has 30% specialty malts, and the base is pilsner malt. The actual wort was made at 155F and hit the correct starting gravity, post boil. My records show the predicted attenuation was 67%, but my actual was 73%, making the beer 3% abv. If I take the pilsner malt out, the specialty malts (two kinds of crystal and a bit of chocolate malt) account for 0.6% abv., according to BeerSmith.

I've made a lot of 4% beer, what I described was the lowest alcohol, highest specialty malt recipe in my archive. I wish I had more recipes to compare with you because I don't doubt your results. I just happened to end up with more fermentability than expected in this one example.
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Offline brewfun

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Re: Fermentability
« Reply #12 on: November 06, 2019, 10:45:43 AM »
But an earlier "low-alcohol" brew had an estimated FG 1.005, an actual FG 1.009, estimated attenuation 65%, actual 28%, and estimated ABV 1.3%, actual ABV 0.5%. Attached is the "Session" page. 50% base malts, 50% crystal malts.

EDIT: Missed some requested info. Predicted SG 1.015, actual 1.012 (I messed that one up a bit?). Mash temperature 74C !).

Interestingly, your graph shows you hit terminal gravity in 24 hours. This makes me wonder about your yeast pitch: freshness, cell count and oxygenation. A graph like that usually means under oxygenation and/or stressed yeast. In that condition, yeast can quickly go into crabtree and only ferment the simplest sugars, ignoring maltose. In most all grain worts at 1.045 to 1.060, this effect results in about 1.5% alcohol before stalling.

So, it looks like there might be more to review.

EDIT: All malt worts tend to have about 3% glucose, which is what ferments so quickly. That means about 1.5% alcohol. I corrected my post, above.
« Last Edit: November 06, 2019, 10:51:32 AM by brewfun »
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Online Oginme

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Re: Fermentability
« Reply #13 on: November 06, 2019, 12:03:06 PM »
So looking at your recipe representing a single data point, you are mashing at 74C which is higher than the recommended range for alpha amylase and way above the range for beta amylase.  I think this skews any correlation of non-fermentable aspects of the crystal malts.  The model for fermentability of the wort hits a max at 71C and does not respond to higher temperatures.  This is intended to mirror the speed of denaturing of the enzymes due to this same high temperatures.  Basically, you are above the range that the model is capable to predicting due to limitations within the software.  That is your issue and not necessarily the potential of the crystal malts.

I think if you petitioned Brad to extend the range for wort fermentability as a function of mash temperature to cover the range up to 74C that might give you a better prediction of what you would obtain.

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Offline PeeBee

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Re: Fermentability
« Reply #14 on: November 06, 2019, 12:07:47 PM »
- So, it looks like there might be more to review. -
'Eck. I'm guilty of derailing my own thread. I was posting a suggestion for enhancing the Beersmith program, but I've mentioned "low-alcohol beer" and look what's happened! (At least my "low-alcohol" brewing hasn't derailed someone else's thread this time).

But - low-alcohol worts are not oxygenated for fear of encouraging spoilage microbes. Dried yeast has more than enough oxygen needs already dealt with. And the yeast will be stressed - there isn't much food! The yeast is only dropping 4-5 gravity points which probably happens in a matter of minutes; the readings in the attached graph are probably too infrequent. S. Lugwigii is becoming popular because it will not touch maltose, so what you say about saccharomyces cerevisiae only fermenting glucose if stressed raises an eyebrow!

I lied about the beer in that attachment: It seems that recipe only had about 20% crystal malt, not 50% (Munich and rye for base malts).

 

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