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Fermentability of various forms of malt


antiphile

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Last night I side tracked a thread by referring to the relative mash efficiencies of various types of malts, including specialty malts. On doing a bit more reading, it seems the way these are more commonly (and more sensibly) compared are by measuring their apparent attenuation (AA) in the resulting beer. So, I'll just stick to that measure.

 

Broadly speaking, here is the AA percentages for the various type of presentations:

 

Base malts approx 80%

 

Light Specialty malts (light crystal, Carahell, Carapils etc around 10 lovibond) approx 74%

 

Medium Specialty malts (around 40 lovibond) approx 60%

 

Dark Specialty malts (dark crystal, Caramunich III etc around 120 lovibond) Approx 54%

 

Dark roasted malts (Roast barley, black patent etc) Around 25 to 30%

 

Malt extracts (depending on brand and colour) Between 50 and 75%

 

Table sugar, dextrose etc Over 95%

 

The Otter brought up an interesting point whether the "as yet unconverted" starches in specialty malts can be more fully converted if mashed with a base grain. I haven't found a direct answer to this one, but purely by reading between the lines, I'm getting the impression the starches might be altered by the higher kilning temps, thereby locking them up and making them totally unavailable for any further use. But I'll admit I don't have a smoking gun on that one.

 

References include:

https://byo.com/hops/item/629-fermentability-advanced-brewing

http://www.woodlandbrew.com/2012/12/fermentability-of-crystal-malt.html

 

 

 

 

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Nice post Antsi.

 

I admit I knew very close approximates to most of the numbers quoted for the various malts already, but what I did find very interesting from a personal standpoint was the apparent attenuation shift as a percentage when mashing at opposite ends of the scale.

Actual mashes performed under test conditions show a decrease in apparent attenuation of more than 6% between wort mashed at 148 °F (64 °C) and 158 °F (70 °C).

The increased fermentability of wort by mashing lower is mentioned a lot in brewing discussions' date=' but it is hard to fathom how much of a difference it makes until I suppose you the brewer do some experiments in that area. A 6% shift in apparent attenuation is a BIG shift!

 

Cheers,

 

Lusty.[/size']

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It probably helps to understand how the two different enzymes actually work to break down the starches during the mash as well. Alpha and beta amylase work differently to each other which I think is why they both result in differently fermentable worts. I can't remember exactly what the difference is but it's easily found information.

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Last night I side tracked a thread by referring to the relative mash efficiencies of various types of malts' date=' including specialty malts. On doing a bit more reading, it seems the way these are more commonly (and more sensibly) compared are by measuring their apparent attenuation (AA) in the resulting beer. So, I'll just stick to that measure.

 

Broadly speaking, here is the AA percentages for the various type of presentations:

 

Base malts approx 80%

 

Light Specialty malts (light crystal, Carahell, Carapils etc around 10 lovibond) approx 74%

 

Medium Specialty malts (around 40 lovibond) approx 60%

 

Dark Specialty malts (dark crystal, Caramunich III etc around 120 lovibond) Approx 54%

 

Dark roasted malts (Roast barley, black patent etc) Around 25 to 30%

 

Malt extracts (depending on brand and colour) Between 50 and 75%

 

Table sugar, dextrose etc Over 95%

 

The Otter brought up an interesting point whether the "as yet unconverted" starches in specialty malts can be more fully converted if mashed with a base grain. I haven't found a direct answer to this one, but purely by reading between the lines, I'm getting the impression the starches might be altered by the higher kilning temps, thereby locking them up and making them totally unavailable for any further use. But I'll admit I don't have a smoking gun on that one.

 

References include:

https://byo.com/hops/item/629-fermentability-advanced-brewing

http://www.woodlandbrew.com/2012/12/fermentability-of-crystal-malt.html [/quote']

 

Some nice links Antiphile. Thanks!

 

Your Woodland Brewing link does seem to indicate the kilning process locks up some unconverted starches, making them permanently unavailable, even when mashing. But that is okay, isn't it? Aren't unfermentable starches what give us mouthfeel?

 

There is still an advantage to mashing specialty grains (vs steeping), however, according to this chart provided by John Palmer in "How to Brew,"

 

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

 

But it seems to me that unless you are using a large amount of specialty grains, say >10%, you are probably better off cold steeping them (perhaps even when doing all-grain). With my recent reading I am at the stage now in my thinking that I can't see the point of hot steeping anything anymore. To me the two options are cold steeping and mashing, or partial mashing- for a kits and bits brewer like myself.

 

Why [partial] mash instead of cold steep? If you are just looking for flavour and mouthfeel from specialty grains you can get them from cold steeping, and some argue they are even superior to what you get from mashing. The main reasons to [partial] mash instead are:

 

1.) to maximize fermentability of the wort, and

2.) reduce starch haze (which reduces spoilage risk), so that you can use larger amounts (ie >10%) of roasted and crystal grains. Starchy character malts with no or low diastatic power, like Victory, Dark Munich, Brown Malt, Honey Malt, etc. should also be mashed.

 

I have read the temperature ranges in the BYO article that alpha- and beta-amylase work at before, as well as the recommendation to mash at 152-153F (66C), which is the middle ground, to get some action from both enzymes. But as I read it again I began to wonder whether the same advice holds for partial mashing? Just thinking out loud here, but if the above is true, does it not make sense to focus on beta-amylase and partial mash at 148F (64C) instead? Or does the middle ground advice still hold?

 

Which brings up another question: what are people using for partial mashes, 2-row or 6-row? Thanks!

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Hi Christina.

I have read the temperature ranges in the BYO article that alpha- and beta-amylase work at before' date=' as well as the recommendation to mash at 152-153F (66C), which is the middle ground, to get some action from both enzymes. But as I read it again I began to think about whether the same advice holds for partial mashing? Just thinking out loud here, but if the above is true, does it not make sense to focus on beta-amylase and partial mash at 148F (64C) instead? Or does the middle ground advice still hold?[/quote']

It's been tough enough dealing with ONE very intelligent & cluey Canuck on this forum over the past few years. It appears we now have at least TWO!! tonguelol

 

If I've understood the article & what it elaborates, then the temperature of the mash simply relates to creating eventual fermentability, & has less to do with how the alpha & beta amylase enzymes impose/contribute their attributes to the final wort. Without looking back on the article it makes mention that the alpha amylase enzymes do there conversions etc. usually within the first 30-45mins. The beta amylase impact on the wort appears to happen much later in the mash cycle. The involvement of the beta amylase in the mash appears to assist in dealing with haze causing proteins etc. to produce a clearer wort if I've understood it correctly.

 

I remember PB2 mentioning a little while back that he mashes (or was it boils? unsure) for 90mins when he wishes to produce a clearer wort. He also poked fun at himself for doing it on a recent Porter recipe of his given that clarity wouldn't be that important with such a dark coloured beer. wink

 

Hopefully PB2 chimes in here & can explain it all more accurately than I have been able to. unsure

 

Which brings up another question: what are people using for partial mashes' date=' 2-row or 6-row? Thanks![/quote']

The Barret Burston/Joe White stuff I use is 2-row I'm pretty sure. I also use some Pilsner malt grain in some instances. I'm guessing it's 2-row too. unsure I'll look into that. wink

 

Cheers,

 

Lusty.

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Most of the malt available to us is 2-row.

 

The temperature of the mash pretty well governs which enzymes are working, which in turn contributes to the overall fermentability of the wort.

 

This here article explains it better than I can lol but basically the two enzymes work in different ways to convert the starches, and they both have optimum temperature ranges in which to do so. The beta amylase is largely denatured by the time the mash gets to the optimum range for the alpha amylase.

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Given Kelsey's retort post, I did have to go back (for my own sanity!) & read the BYO article to find the exact part of the article I was trying blindly to refer to. Kelsey's post is spot on, so no intent to refute any of that, just clarify what I wanted to put forward, with some factual reference from the article.

While the mash temperature is clearly the most important factor in controlling fermentability' date=' there are others. The time for the rests during mashing also affects fermentability. Modern well-modified and highly enzymatic malts are known for their quick conversion of starches to sugars. Tests prove that the great majority of starches are converted in the first 5–10 minutes as they are hydrated and gelatinized and brought to the correct temperature. This has led some brewers to conclude there is little benefit from mashing for a much longer period of time. However, conversion does not tell the entire story. There is evidence that beta-amylase takes somewhat longer to work than alpha-amylase. Therefore a longer rest (up to 90 minutes) will encourage greater fermentability, although the effect seems to be much less than that of the temperature itself. Common conversion rests for mashing with modern malts are 30–60 minutes.[/quote']

That's all. Take that for what you feel it is worth. wink

 

Lusty.

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Yep, that's pretty much how I understand it too mate. Also it goes along with the description of Hochkurz mashing on the Braukaiser site - there are two rests at 63 and 69/70 and the duration of these rests affects the fermentability too. I'm currently experimenting with this at the moment. The first one I did 70 mins @ 63 and 20 mins @ 69 - this fermented out to 1007. The second one I decreased the 63 time and increased the 69 time by 10 mins respectively, and I'll find out what effect that had when I ferment it after this current batch. Once I work out where I want the rests, I'll stick with it. It's all very interesting stuff. biggrin

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I'm currently experimenting with this at the moment. The first one I did 70 mins @ 63 and 20 mins @ 69 - this fermented out to 1007. The second one I decreased the 63 time and increased the 69 time by 10 mins respectively' date=' and I'll find out what effect that had when I ferment it after this current batch. Once I work out where I want the rests, I'll stick with it. It's all very interesting stuff. [img']biggrin[/img]

Agreed. Even though I don't step mash, doesn't mean I'm not interested in how it plays out with a specific malt bill.

 

If you gather some info with various step mash combo's using the same malt grist & yeast prep/pitch rate, I'd certainly be interested in your results, as I'm sure others (even more so) on this forum would. cool

 

If it doesn't have that malt grist/yeast prep linkage, the results would become a little 'hodge-podged'. sleeping

 

Cheers,

 

Lusty.

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Yep that's what I'm doing - this experimentation is only happening with my pilsner recipe, so it is the same malt bill and yeast prep each time. Ales I'm happy with a single infusion in the mid 60s somewhere. I may even do that on these pilsners one day if I get too lazy to do Hochkurz mashes. lol

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Thanks for the link Kelsey; it was interesting! smile

 

To get back to my own question about partial mashing, I found the quote below (from the article) helpful. It is talking about the enzymatic power of the mash:

 

"If large amounts of highly kilned base malts (like Munich) or large amounts of adjuncts (which are unmalted grains that do not contain a significant amount of enzymes) are used, the mash will have a lower enzymatic strength. Thus less maltose is produced and the fermentability suffers. This needs to be counteracted with a lower rest temperature and/or a more intensive mashing schedule."

 

A typical partial mash for a 23 liter batch might be 1kg 2-row plus 1 kg specialty grains. The diastatic power (DP) of this mash is 70, well above the minimum.

 

http://beersmith.com/blog/2010/01/04/diastatic-power-and-mashing-your-beer/

 

In which case the generally recommended mash temperature of 152-153F (66C) is fine. If you instead use 0.5kg 2-row, and 1.5kg of specialty grains, the DP of the mash is only 35, barely above the minimum. In this case use a lower temperature, like 148F (64C). You can see from the chart in the beersmith article that depending on anything other than 2-row/6-row for your enzymes --like Pilsener, British Pale malt, Vienna, or Munich-- can quickly run you into trouble.

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I agree wholeheartedly with all of you (jeez! I am going mad!)

 

The thing that struck me most was the comment (that may have been in the BYO link) that we all seem to want to concentrate on the OG, when we should be more focussed on the FG (or something like that). And that's precisely what I've been doing for the last half year or so without explicitly acknowledging it to myself as a goal. And while I may be getting closer, it certainly hasn't been mastered. In fact at the moment I claim a personal victory if the FG is within 2 brewers points either way of the predicted level (which in truth isn't really good enough).

 

There are so many variables including the system, the mash temp, mash temp steps, mash times, grain water ratios, how the sparge is done, efficiency, yeast type, even the crush etc etc etc. But I like to think I'm slowly getting closer.

 

Like you all, I try to concentrate on one aspect at a time -- and the last few months has been the mash steps. More often than not these days I like decocting because its so much easier to hit the steps accurately when mashing in the esky. And more often than not, these steps are at 40, 51, 63, 68.5 and 76 (and usually I'll dough in at 21). I keep seeing comments on some fora about this being crazy, unnecessary, a waste of time and even bad for the beer with all the highly modified malts these days. But I'm happy to bite my tongue and carry on because the final outcome is extremely predictable for the mash efficiency for me. Always within 1% for the last 6 3V batches. I also cheat a bit too because I rarely have much more than 10% of specialty malts in the grain bill (and thus, the mash tun).

 

After that, my next step is to concentrate on a consistent and predictable brewhouse efficiency (which can swing 3 or more percent at the moment), and then other factors like yeast etc etc.

 

Now, Christina, Otter and Prof Lust, I want you to write out (by hand) one thousand times:

antiphile is not being excessively anal.

 

Photocopies will not be accepted; original copies only.

 

Edit added 1:07 pm. I forgot to throw in my worthless opinion on 2 row VS 6 row. Here in Aus, it's not terribly easy getting 6 row. It is around if you go searching for it, but by default 2 row is the standard for everything. In a way its a bit of a shame because (and I'm very dangerously working solely from a demented memory here) I understand that generally 6 row has much higher diastatic power and produces considerably more malty flavour than the equivalent 2 row grain.

 

It sounds as though it may be more freely available in the land of the Brunswick, Christina.

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Yes Phil, I suppose FG gives you information about the body and sweet vs dry flavour of the beer. The only thing thing knowing OG is useful for in addition to this is allowing you to roughly gauge how many it will take before you fall asleep on the couch! Which always seems to be much easier to do with a hypnotically breathing and asleep cat sitting in your lap. So maybe the sleepy cat presence factor should also be considered in any standard formula.

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  • 2 weeks later...
hit the steps accurately when mashing in the esky. And more often than not' date=' these steps are at 40, 51, 63, 68.5 and 76 (and usually I'll dough in at 21).

[/quote']

 

Got 2kg of light malt grain today so ready to give it a go. Have my 6 litre rice cooker inside my esky with a controller attached so ready to try any temperatures and times that I can throw at it. I think for my first attempt will stick to something like 66@70min, too many choices though.

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