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Thick mash vs. thin mash?

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dsuarez

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Hey there,

I know the consistency of your mash definitely effects the character of the finished beer, but how so. somebody told me that one fosters more proteolytic activity, where the other fosters diastatic activity. Can anybody shine some light on the differences that come from mashing thick vs. thin

FYI I used to mash pretty thin, so that there was a layer of water ontop of the grains, but now I mash on the thicker side, so the mash looks like slightly soupy oatmeal. dont know why though
 

malkore

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I believe the idea is that a thicker mash means the enzymes are less diluted, so they are more available to actually convert sugars from the grains.

A thinner mash is easier to rinse the sugars during sparging, but too thin and you sacrifice efficiency. Thus you have to find that happy middle ground.

I could be wrong tho.
 

GilaMinumBeer

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"At mashing temperatures the survival and activity of the proteolytic system of enzymes is extremely dependent on mash thickness."


"Changes in mash thickness (liquor/grist ratio) have significant effects on mash performance (Hind, 1950; Hopkins and Krause, 1947; Harris and MacWilliam, 1961; Muller, 1989; 1991; Table 4.14). Very concentrated mashes, (liquor/grist <2:1 ml/g), are difficult to mix and pump, extract recoveries are reduced, starch conversion is slowed down, worts are more concentrated and viscous, TSN and FAN are increased and more high molecular weight nitrogenous substances remain in solution, but a lower proportion of hydrophobic peptides (relative to the amount of extract) are present, causing `high gravity' beers to have poor head retentions (Bryce et al., 1997). In the concentrated mashes both the enzymes and their substrates are more concentrated. Some enzymes (proteolytic enzymes, disaccharidases) are more stable in concentrated mashes producing higher proportions of TSN and hexose sugars respectively."


"The high concentrations of sugars and dextrins present in thick mashes can inhibit the amylases. Enzyme inhibition is due to the reduced availability of free water as well as to the sugars acting as competitive inhibitors."



"As the grist hydrates water is bound, and there is a rise in temperature caused by the release of heat (the `heat of hydration'). As the mash proceeds water is utilized in hydrolyses, a water molecule being consumed when any bond is split. Some water is more or less firmly bound (by hydrogen bonding) to starch, to sugars in solution, to glucans, to pentosans and to other substances reducing the concentration of `free' water. In all-malt mashes and mashes made with 50 : 50 malt and barley or wheat starch the extract recovered falls very sharply as the liquor/grist ratio is reduced below about 2.5 (Fig. 4.14). Generally, altering the liquor/grist ratio at values over 3 has comparatively minor effects, but these are not necessarily negligible. In a particular case mashing with a liquor/grist ratio of 2.5 : 1 gave an extract of 291 l ë/kg, while at a ratio of 7 : 1 the extract was 311 l ë/kg. The extent of water binding becomes progressively greater as mashes become more concentrated and there is insufficient free water to permit the gelatinization of much of the starch. The addition of more enzymes to a very thick mash does not quickly convert the ungelatinized starch and so does not enhance the extract obtained."



 

david_42

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Homebrewers seem to favor very thick mashes (1.25:1 or so), for reasons I've never understood. Maybe it's the urge to cram as much grain as possible into their systems. When I see people trying to do 14 lb mashes in a 5 gallon tun, I can only wonder.
 

Kilgore_Trout

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I've gone to a thin mash (2qt/lb) and had better efficiency.

I can't tell a difference, but I brew mostly thinner styles anyway.
 

Donasay

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I crammed 31 lbs into a 10g cooler once, learned never to do that again.
 

Kaiser

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Here you go, very good information here!

I consider some of the statements outdated and John doesn’t state them like this in the 3rd edition of his book.

Thick mashed favor protein break-down mostly b/c the life of the enzymes is extended and a thick mash doesn’t inhibit the protein enzymes as much as it inhibits starch conversion processes.

Here is where my experiences and knowledge differs from most statements about mash thickness:

But for starch conversion you have 2 main effects that work against each other: thick mashes cause the starch to be gelatinized at a slower rate and the enzymes are not as efficient due to inhibition by the higher sugar concentration but the enzymes live longer. Thin mashes cause a faster conversion b/c of starch being gelatinized faster and enzymes working more efficiently. But the enzymes are not as stable an may not live as long.

The result is that mash thickness has no effect on fermentability because the faster denaturation of the beta-amylase in thin mashes is compensated by it being able to work more efficiently during the shorter time it is active.

But it is different for efficiency. The a-amylase, which is responsible for converting starch and contributing to efficiency, is fairly stable at mash temps. This means its time of being active is not so much affected by a thinner mash. But it is able to work more efficiently. The net result is that thin mashed result in a faster and possible more complete conversion that thick mashes with the same other mash parameters (crush, temp, time,. pH …)

as for why most of us mash thick, I assume that it has its origin in English style brewing (single infusion with low water/grist ratio) and that someone started to say that 1.25 qt/lb is an optimal mash thickness. And that idea persists although I have not found any scientific basis for it.

Kai
 

cactusgarrett

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Homebrewers seem to favor very thick mashes (1.25:1 or so), for reasons I've never understood. Maybe it's the urge to cram as much grain as possible into their systems. When I see people trying to do 14 lb mashes in a 5 gallon tun, I can only wonder.
I used to favor a ratio around there for the space issue, then i did with the idea that it gave me more batch sparge water to play with. I figured: if there isn't much difference in extraction efficincy, a thicker mash would at least give me more sparge water to rinse my grain & yield a better efficiency into the kettle.
 

WortMonger

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So Kaiser, you would rather someone do a thick protein rest (if one was needed) and then thin up to your sacchrifiction rest(s) close to maybe 2qt/lbs ratio? I had always heard this was better for protein conversion, (but I was also always under the impression that alpha-amylase did better in a thicker mash) and then you were supposed to thin-up to your alpha and then again for your beta-amylase rest for it to work best. If a-amylase really can work just as good or better in a thinner mash I'm all for it. I would just fill up to ratio for my alpha rest and then heat up for my beta without having to worry about extra water (because it would already be there). Am I reading you wrong or on the write track Kai?
 

Kaiser

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You got it right except for the order of alpha and beta. b-amylase is the one that denatures in the 150s and produces maltose. a-amylase is the one that is still active into the 170s and converts the starch into dextrins.

A protein rest is more effective when done with a thinner mash but you have to keep in mind that for most malts we are not looking for the most effective protein rest anyway. And if a thin protein rest is less effective it can also be counteracted by simply holding the rest closer to 120 or extending it. So it is perfectly fine to mash thin all the way if that works better or to start out thick and infuse hot water to reach the next rest.

Kai
 

WortMonger

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I feel like an idiot and am not even going to bother editing my dumba$$ post. Thank you Kaiser the thin-the-whole-route thing is really going to help my HLT situation. I've always been a 1.25'er, so to hear you speak of thinner mashing is a blessing. I can't believe sleep deprivation has gotten so bad I confuse alpha and beta amylase rests, lol. My roomates the night before last and dogs last night kept me up. I'm working on about 6 hours sleep in the last 48.
 
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