how important is mash thickness, I way under measured...

Mash thickness has a greater impact on efficiency than anything else. So, unless your efficiency suffered...don't worry about it.

 

In addition to reducing extraction efficiency, a thicker (to a degree) mash favors beta amylase activity by helping to better shield it from exposure to warmer temperatures since grain has a lower heat capacity than water. Provided the thicker mash is of a long enough duration (beta amylase reduces sugars at a slower pace), this ultimately can lead to a more fermentable wort. An extremely thick mash though can actually inhibit beta amylase activity via crowding / product inhibition. Too much of the product being around can inhibit the enzyme from being able to work on the substrate. It just can’t find it as quickly as needed (traffic jam = opportunity cost). Literal inhibition can also be due to presence of other products: Ie. Physical presence of glucose can prevent the cells from being able to bring in the maltose for enzyme reactions. Just remember that thickness alone doesn't always have the effects described at any given temperature. Temperature can override some of these effects to a degree and/or some of these effects only become prominent at certain mash temperatures. For example, mashing at a low temperature is going to promote beta amylase activity more (regardless of thickness) than using a thicker mash at a warmer temperature. But using a thicker mash at a warmer temperature will promote more beta amylase activity than a normal mash thickness at that same warmer temperature might (due to shielding).

 

A thick mash will NOT give you fuller mouthfeel or lower attenuation -- that's a myth. Your beer will probably turn out just fine as long as you sparged enough to hit your desired pre-boil volume. No worries. Have a homebrew.

 

Yeah never mind the detailed scientific explanation I gave routed in chemistry of which I can also provide industry recognized references supporting. dmtaylor simply calls hogwash without actually addressing the argument put forth, so I guess his paper covers my rock

http://braukaiser.com/download/Troester_NHC_2010_Efficiency.pdf

"mash thickness: Thick mashes impede starch gelatinization and inhibit alpha amylase activity.


http://howtobrew.com/section3/chapter14-6.html

Chapter 14 - How the Mash Works

"There are two other factors besides temperature that affect the amylase enzyme activity. These are the grist/water ratio and pH."

"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."

References
Fix, G., Principles of Brewing Science, Brewers Publications, Boulder Colorado, 1989.

Moll, M., Beers and Coolers, Intercept LTD, Andover, Hampshire England, 1994.

Noonen, G., New Brewing Lager Beer, Brewers Publications, Boulder Colorado, 1996.

Maney, L., personal communication, 1999.

Lewis, M. J., Young, T.W., Brewing, Chapman & Hall, New York, 1995.

Briggs, D. E., Hough, J. S., Stevens, R., and Young, T. W., Malting and Brewing Science, Vol. 1, Chapman & Hall, London, 1981.

Wahl, R., Henrius, M., The American Handy Book of the Brewing, Malting, and Auxiliary Trades, Vol. 1, Chicago, 1908.

Broderick, H. M., ed., The Practical Brewer - A Manual for the Brewing Industry, Master Brewers Association of the Americas, Madison Wisconsin, 1977.

 

Relax. Run your own experiments and see what you get. I bet you haven't. Thick mash = thick beer has not been my experience.

 

how much lower are we talking?

 

There was some experiments run on this very thing by Kai Troester and surprisingly he found that there was no effect on final attenuation/ferementability from mash thickness, and in fact newer (2000's) technical brewing literature asserts that mash concentration doesnt have much effect in well modified malts.

There may be some small differences in extract but from what Ive seen that only occurs at the wide ends of the spectrum, Troester's bottom graph shows this, but I cant recall what he did for his mash and whether he sparged it or not, I'll have to go back and read (I do know however that most of my beers tend to be below 67C for the mash so that may also be something to note for the OP - What temp did you mash at??

-From Effects of Mash parameters on attenuation and efficiency

 

Trust me, I'm not worked up over your position. If anything is remotely bothersome to me, it's that you originally provided no reason for your claim.

 

Thanks for the "food for thought" ryane! I'll have to re-read Troesters experiments to cross reference all of the parameters (mash temp, mash thickness, and mash length) to make my own assessment of his findings. I know that the enzymatic inhibitors I mentioned ("crowding" and "product inhibition") are conversion inhibitors. But I currently do believe that, theoretically speaking, there are certain mash scenarios (specific temp and duration combinations...most likely a longer mash in a temperature range just above beta amylase's peak activity range in the "brewers window") in which the "heat shielding" concept would promote more beta amylase activity. The question of course is whether or not that potential increase in beta amylase activity is substantial enough to actually produce a notably more fermentable wort. To that end, I admit that I do not know and I am merely speculating that it is indeed plausible.

 

@ryane

What we do know is that:

1a. 65C is generally considered to be the end of the peak beta amylase activity range
2a. 70C is generally considered to be the point where beta amylase is significantly denatured

If I'm interpreting Troesters graph correctly:

he has the following data points relevant to the concept of "heat shielding" potentially increasing fermentability that I'm endorsing as plausible:

thick mash: about 85% fermentable @ 66.25 C and the same @ 67.25C
thin mash: about 85% fermentable @ 65.75 C

unfortunately, what his graph doesn't have is:

1b. another thick mash data point at a mash temperature below 65C
2b. other thick mash data points at various mash temperatures between 67.25C and 69.25C
3b. other thick mash data points at various mash temperatures above 69.25C
4b. other thin mash data points between 65.75C (85% fermentability) and 69.25C (80% fermentable)
5b. another thin mash data point above 69.25C (80% fermentability)


Now if he had:

1b. And that thick mash data point at a mash temperature below 65C and it showed to be no higher than 85%, we could posit that the "heat shielding" of the thick mash is indeed a factor in his findings of 85% fermentability @ 67.25C (2.25C above the peak beta amylase activity range cut off point of 65C). The main counterpoint to this though is that his mash tun dropped 2C over the course of the mash, allowing his initial 67.25C mash temp to regress back to 65.25C which is only 0.25C above the upper limit of the peak beta amylase activity range cut of point of 65C.

2b. And those other thick mash data points at mash temperatures above 67.25C showed exactly where the 85% fermentability result began it's drop towards the 80% result @ 69.25C, it would further support the possibility of "heat shielding" having a notable impact on fermentability, since the mash would have been even more than 0.25C beyond the upper limit of the peak beta amylase activity range cut off point of 65C after losing 2C over the course of the mash.

3b. We could see if the "heat shielding" potential of a thick mash could indeed maintain fermentability results (80% at 69.25C) found just before the 70C significant beta amylase denaturing point.

4b. And those thin mash data points between 65.75C (85% fermentability) and 69.25C (80% fermentability) were matched against added 2b. thick mash data points, we could better isolate the difference that the thickness itself had on fermentability at those various temperature points.

5b. Then we could match them against the points from 3b. to better isolate the difference that the thickness itself had on fermentability at those various temperature points.

Based on what he does have:

1c. I see no data that contradicts the plausability of "heat shielding" increasing fermentabilty under certain mash temp/time scenarios.

2c. I see limited data supporting (not conclusively though) the plausability of "heat shielding" increasing fermentability (the 66.25C and the 67.25C thick mash resulting in 85% fermentability despite both starting (and the latter BARELY ending) above the generally accepted 65C upper limit of the temperature window for peak beta amylase activity.

3c. I see a need for the missing data points I highlighted to conclusively support or reject the "heat shielding" concept.

 

As I said... run some experiments as you see fit.

 

How much coffee have you had this morning???

 

I don't drink the stuff actually. Just geeking out on brewing science

 

Maybe I should start. Just realized that I reversed his thin and thick mash data points. Where I originally wrote that Troester had plotted:

thick mash: about 85% fermentable @ 66.25 C, 85% @ 67.25C, and 80% @ 69.25C
thin mash: about 85% fermentable @ 65.75 C

He actually plotted:

thin mash: about 85% fermentable @ 66.25 C, 85% @ 67.25C, and 80% @ 69.25C
thick mash: about 85% fermentable @ 65.75 C

He also plotted

thick mash: about 77% @ 70.75C and about 66% fermentable @ 74.25C

Reinterpretation to follow soon (beats doing household chores today)

 

http://en.wikipedia.org/wiki/Misleading_vividness

I'll just leave this here....

 

thick mash: 85% @ 65.75C and 77% @ 70.75C

We still need data points ranging from say 60C - 65.5C in order to determine if heat shielding is offering a benefit to fermentability beyond the 65C upper limit of the beta amylase peak activity range. We also need additional data points between 65.75C and 70.75C to determine exactly where fermentability starts to drop, since 70.75C is already beyond the point (70C) where beta amylase significantly denatures. It would also help to have data points stemming from a mash tun that remained at a constant temperature throughout the duration of the mash. This would eliminate yet another variable allowing us to examine the correlation btw mash thickness, mash temperature, and amylase enzyme activity more precisely.

thin mash: 85% @ 66.25 C, 85% @ 67.25C, and 80% @ 69.25C

A thin mash producing 85% attenuation @ 67.25C (2.25C beyond the 65C upper limit of beta amylases peak activity range) kind of sets the bar for the thick mash and heat shielding. I'd assume, to prove that heat shielding benefits attenuation significantly around the upper temperature limit of the peak beta amylase activity range, the thick mash would need to produce at least 85% attenuation @ 67.25C. We would also need data points above 67.25C and below 69.25C showing that the thin mash attenuation decreased prior to the thick mash attenuation in that range. What we do know is that the thin mash attenuation does take a nose dive somewhere between 67.25C (85%) and 69.25C (80%). We also know that the thick mash attenuation takes a nose dive somewhere between 65.75C (85%) and 70.75C (77%).

Take away:

Troesters results (now that I believe I have interpreted the data points correctly) still lack the essential data points needed to prove or disprove the potential for heat shielding to have significance with regards to attenuation.

Based on Troesters results, the best way to prove or disprove the potential for heat shielding to have significance with regards to attenuation might be to:

1. Analyze attenuation results for both a thick and a thin mash at various temperatures btw say 65.75C and 72.75C
2. Determine at what temperature in that range, the attenuation of one mash thickness drops below the attenuation of the other with all other variables remaining constant.

Of course having a mash tun that remains at a constant temperature throughout the duration of the mash and measuring both mash thickness attenuation results at varying temperatures in the say 60C - 75C range by say 0.5C increments would give us a much better overview.

 

Im a little scared what might happen if you do start drinking it.............

That said, I think it would be interesting to go back and better design the experiments he did to draw some more finite conclusions. His first crack at it was great and I think eliminated some things so we could better focus on others.

Now that Im away from a university research lab I miss the access to all the great analytical instruments I once had. After I defended my dissertation I did quite a thorough analysis of candy syrup (sugar types, nitrogen etc content, ash content, and ran it through an HPLC MS to try and identify the cocktail of aminos they add to make it) Im gonna have to dig out that data and write it up for others to read

 

Won't you be surprised to find out this 'mistake' ends up being your best brew evah.