Mash Thickness: Questions

So, I recently upgraded my 5gal MLT to a 10 gallon this past weekend. At 5 gallons, my MLT pretty much maxes out with 12-13lbs of grain at 1.25 quarts or water per pound of grist. I've read in How to Brew and other books about how mash thickness will effect fermentability and efficiency, and therefore the final gravity of the end product. I was thinking on doing an experiment where I would take the exact same recipe, but mash each batch separately at two different temperatures. It would be a fun experiment, but if someone else has already done this, I'd love to hear of your experience and results.

I batch sparge, and get around 70% efficiency. I want to do one batch at 1.25 quarts/pound and then the other at 1.5 quarts/pound. For the following recipe, which is a simple Pale Ale I should end up with the following numbers:

Batch Size: 5.5 Gallons
OG: 1.053
FG: 1.013
ABV: 5.24%
IBU: 36.1

Simple 5 gallon West Coast Pale Ale recipe:
Grain Bill
9.0 lbs 2-row Pale Malt
2.0 lbs Vienna Malt
0.5 lbs Crystal 60L

Hops
.75 oz Centennial - 60 min
1.0 oz Willamette - 15 min
1.0 oz Willamette - 05 min

Wyeast 1056 Activator
Irish Moss (1/2 tsp last 15 minutes of boil)

I think the change in temperature is going to have more effect on the differing products then the water to grist ratio.. Regardless, the kind of controlled experimenting you suggest is really useful in learning as you make your own choices about how you want to make your beers.

If you ever want to do an English style Pale Ale or Bitter, you may want to go for a thick mash (0.9 - 1 qt. per lb.) I find that reducing the mash water from 1.25 to 1 qt. per lb. has more effect than increasing the mash temperature by 4 - 5 degrees. This probably wouldn't work so well for an APA, and I've never tried mashing with more that 1.25 qt. per lb.

I agree with Brewpastor, that experiments like this are really useful (if you take notes).

-a.

as i understand it, a thinner mash will result in a more fermentable wort. does more fermentable = higher OG or does it mean sugars have been broken down further than dextrose to simpler, more fermentable sugars?

ajf said:

If you ever want to do an English style Pale Ale or Bitter, you may want to go for a thick mash (0.9 - 1 qt. per lb.) I find that reducing the mash water from 1.25 to 1 qt. per lb. has more effect than increasing the mash temperature by 4 - 5 degrees. This probably wouldn't work so well for an APA, and I've never tried mashing with more that 1.25 qt. per lb.

I agree with Brewpastor, that experiments like this are really useful (if you take notes).

-a.

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For what reason do you recommend doing this? Does it help with the final gravity, or just taste overall? At some point I would like to make a english style bitter, but I think I'll stick with an APA for this experiment. For no better reason than it is the style I like to consume the most . If I get nothing else out of the experience, I'll have 10 gallons of good stuff!

scottfro said:

as i understand it, a thinner mash will result in a more fermentable wort. does more fermentable = higher OG or does it mean sugars have been broken down further than dextrose to simpler, more fermentable sugars?

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From what I understand about this, the more fermentable the wort, the lower your final gravity will be. I know the final gravity is also influenced by temperature, length of fermentation, and the attenuation of the yeast used. However, you've hit my question right on the head; I'm not really sure what will happen but I hypothesize that the thinner mash will result in a more fermentable wort and lower gravity. Not sure about this though...it could just mean better efficiency. Either way, I learned something and made beer!

More fermentable" means lower FG, and a lighter, drier tasting beer.
The thicker mash at 150 - 152F works really well for my normal (English) brews, but I tried it in an APA some while ago, and the results were not good.

-a.

ajf said:

I find that reducing the mash water from 1.25 to 1 qt. per lb. has more effect than increasing the mash temperature by 4 - 5 degrees.

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Based on my experience, I would say the opposite is true. I think your mash temperature has much more effect on how the enzymes work and the fermentability of the wort than the thickness of the mash.

4-5 degrees in your mash can make a substantial difference in the enzymes at work. I don't see how 1.25 vs 1.00 qt/lb mash thickness will make nearly as much of an impact if the temps are identical.

I tend to agree in the big picture and really would encourage doing all you can to peg specific mash temperatures and see what differing temperature does to a recipe. Once you have that pegged, if you want to look at thickness you will be able to do so with a richer base knowledge based on mash temperature.

The other piece that really should not be ignored is fermentation temperature control. But that is a whole other can of worms isn't it?!

ajf said:

If you ever want to do an English style Pale Ale or Bitter, you may want to go for a thick mash (0.9 - 1 qt. per lb.) ...

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TwoHeadsBrewing said:

For what reason do you recommend doing this? Does it help with the final gravity, or just taste overall? ...

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I think the reason for mashing English style ales thicker is historical, as it supposedly produces a beer that is more "authentic". Thick mashes for English ales are recommended in Designing Great Beers by Ray Daniels and Mild Ale by David Sutula

As for the effect of mash thickness, here is what John Palmer has to say:

From How To Brew by John Palmer (Chapter 14, Section 6)

The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature.

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Thin mash = more fermentable wort, ligher beer
Thick mash = less fermentable wort, sweeter, maltier beer.

It's interesting that English ales are mashed thick, but often (not always) at low temps (like 150 to 152, on average). The interplay between temp and thickness might be what gives English ales their unique malt character.

I don't think you'll see much of a difference between 1.25qt/lb and 1.5 qt/lb. However, as someone else mentioned about the British beers, you will see a difference between 0.9 qt./lb. and 1.5 qt./lb.


TL

Lil' Sparky said:

Based on my experience, I would say the opposite is true. I think your mash temperature has much more effect on how the enzymes work and the fermentability of the wort than the thickness of the mash.

4-5 degrees in your mash can make a substantial difference in the enzymes at work. I don't see how 1.25 vs 1.00 qt/lb mash thickness will make nearly as much of an impact if the temps are identical.

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Let me ask you. Have you ever tried mashing at 1 qt per lb grain? or do you just think this as your post infers ("I think your mash temperature has much more effect ...")

I did conduct a series of experiments with different mash thicknesses as well as different temperatures, although I never got above 1.25 qts/lb. My post was based on the results of those experiments, not a gut feeling.

-a.

For yrs I mashed with 1 quart per pound with no negative effect and much success. I now typically use 1.3 because it works well with recirculation in my system. I really can't say there is a big difference and I do know that the comp. scores have not changed greatly between the two ratios.

Brewpastor said:

For yrs I mashed with 1 quart per pound with no negative effect and much success. I now typically use 1.3 because it works well with recirculation in my system.

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This is exactly my experience, and what I based my comments on. I started with 1 qt/lb because that's what the charts in Papazian's book were geared for if I remember correctly. I made the switch when I started recirculating the mash because 1 qt/lb is a little too thick for that. I didn't notice any difference in the final product for the same recipes.

No disrespect intended, ajf. I was just commenting that I find that mash temp seems to have more impact than does mash thickness, although admittedly I haven't performed the cool scientific experiments you have. Maybe the fact that I recirculate has something to do with it. If it sat without recirculating, maybe I would see a bigger difference. Do you recirculate your mash?

No, I don't recirculate my mash, and I would hardly describe my experiments as cool or scientific. It could well be that equipment and ingredients have a noticeable impact on the effects of mash thickness. Since I started AG in '92, I had always used 1 qt/lb with variable results. By the time I joined this forum in late '05, I had found a great local supplier of Munton's Maris Otter, Crystal (55L) and Dark Crystal (140L). With these grains, my brews (special bitters, strong bitters, and the occasional EPA or English style IPA) had gotten amazingly consistent being mashed at 150F - 152F depending on the brew.
Only problem was, almost everybody on this forum said you should use 1.25 qt/lb, so I tried it on a special bitter. The only other change was that I mashed at 154 instead of 152.
It turned out to be a very thin tasting beer, and the FG was about 2 points lower than I was getting with the thicker mash.
I repeated the experiment another 4 times, varying the mash temperature between 154 and 156. Each time, the results were the same, although the higher mash temperatures did make a small difference.
I then reverted to my normal practice, and got nice malty flavoured beers again.

-a.