Mash Temps

[PieOPah]

Hi,

What are the ideal ranges for mashing temps? Also, how does this effect fermentability/final beer.

In general I have always tried to hit about 68oC but have no idea what difference this is making when I don't (and I never adjust because I don't know which way to go)

Thanks.

[steve_flack]

It's complicated as mash thickness also plays a role in it but generally the warmer you mash the less fermentable wort you get. So if you want a dry beer aim for a lower temperature and higher for a sweeter beer with more residual sugars. So for an IPA aim for fairly dry say 64C and for a mild where the beer is weaker and you want a bit more body I'd go for 68.

Generally a thiner mash produces a sweeter beer.

It's all down to the differing temperature profiles for the activities of the two main enzymes involved in mashing. The profiles are not the same (they prefer different temperatures).

Generally mashes are very forgiving and anything between 63-69 will make a reasonable beer. It's just if you want to try and tweak the process to get a certain type of mouthfeel then being a bit more accurate with temps is an idea. You can also change your grain bill to achieve similar effects by using malts with more residual sugars (pale crystal malts for example) or by using adjunct such as corn, rice or a small amount of sugar. Generally this is what I'd do and just stick with 65-66 as the mash temp for everything

[SteveD]

Ok....Some generalised potted info,

There are two enzymes present in malt that we are principally interested in during mashing:-

Beta amylase converts starch to maltose - fully fermentable sugar. It also converts dextrins - partially fermentable sugars to maltose.

Alpha Amylase converts starch to dextrins.

The nature of these, and most, enzymes is that they work best within certain temperature ranges. Too low, and they work too slowly, too high and the heat will denature, ie destroy, them.

Beta Amylase works best at around 60c. Alpha Amylase works best at about 70c. As a rule of thumb in mashing we aim for about 65-66c as an average temperature producing a balanced wort in terms of fermentability (maltose) and body/mouthfeel (dextrins).

The effect of mashing nearer 60c is that B-amylase works better and A-amylase is impaired resulting in proportionally more maltose and therfore more fermentability, but less dextrins and therefore less body. This tends to give a thinner but more alcoholic beer. Mashing nearer 70c gives the reverse. B-amylase is impaired and A-amylase works better resulting in proportionally more dextrins and therfore more body, mouthfeel and residual sweetness, but lower fermentability. You get a sweeter, heavier, but weaker beer.

Choosing your mash temperature within the general range of say 62-68c will enable you to alter the character of your brew to suit what you want, though as long as it's between 60 and 70c you should be fine in terms of full conversion of starch to sugars.

Some people start the mash off nearer 60c and then raise it to nearer 70c half way through to utilise the enzymes at their most efficient. It's fairly common to raise the mash temp to about 77c right at the end of mashing to kill off any further b-amylase activity, while still allowing dextrin production if there's any starch left. It also thins the wort for easier run off. Running off at 65c could mean that the B-amylase continues to convert dextrins to maltose for an extended time which wouldn't really be desirable if you want body and an off-dry beer.

All the twaddle above can be summarised into the rule of thumb "mash cool for strength, mash hot for flavour"

Hope that helps,

Steve

[PieOPah]

Thanks Steve, that's perfect.

I am making a sweet stout tomorrow but due to me using lactose, I don't want it to be too sweet. Will look at mashing at the lower end of the scale My mash is also going to be fairly thin I imagine. I am using 2.5 litre per Kg but around 1.5kg of the grain bill is cereal (shreddies, cornflakes and rice crispies) which won't absorb anywhere near as much liquid as the grain will.

EDIT: Thanks both Steve's

[SteveD]

Ahh the two Steves concur

[Frothy]

http://www.howtobrew.com/section3/chapter14-1.html

Frothy

[Orfy]

I think a few of you guys are consistently doing thinner mashes than I've seen recommended (and I do) and it doesn't seem to be doing you any harm.

[steve_flack]

Generally a thiner mash produces a sweeter beer.

are you sure about that Steve

It's a minor effect but thinner mashes have reduced fermentable sugars. I think it's due to the reduced stability of beta-amylase in thinner mashes.

FWIW, I've always done fairly thick mashes but I'll soon be moving to thinner ones. I'm not unduly concerned about the effect of mash thickness.

[steve_flack]

so diluting the mash later give the enzymes more room to work.

The reason I've seen given for the opposite claims almost the opposite - that the amylases are more stable with their substrates. When they're floating about in a thinner mash they fall apart quicker.

Who knows?

[Orfy]

I never test PH and have never had any problems but thinking about it if I increase my mash ratio I'll my increasing the PH causing a potential problem. What do you think?

[mysterio]

Line mentions that a stiff mash is better at initiating the reactions (but not why), he goes onto say that the enymes 'dont get on together' so diluting the mash later give the enzymes more room to work.

The proteolytic (?) enzymes prefer a stiff mash, while the saccharification (?) enzymes prefer a thinner mash, I believe.

That's why if you're doing a protein rest (unnecessary with British malt IMO), it's beneficial to do the 50C rest with a very thick mash, then infuse water up to the saccharification rest.

To be honest, I've always found yeast choice makes the biggest impact on the dryness of the beer.

I never test PH and have never had any problems but thinking about it if I increase my mash ratio I'll my increasing the PH causing a potential problem. What do you think?

I doubt it Orfy!

[Orfy]

Surely diluting the Acid Mash with more neutral water will raise the PH of the mash or am I missing something?

[Jim]

Intuitively, you would expect adding more water to an acid solution would decrease the acidity (i.e. raise the pH). Intuition can be a dodgy thing in chemistry, though!

In practice, however, this seems to be true.

[Orfy]

I think I'll go with thinner mash then, it;ll reduce the amount of sparge water I need.

There's a possibility my next two batches will be Hob Goblin so it's an ideal way to see the difference.

[SteveD]

Surely diluting the Acid Mash with more neutral water will raise the PH of the mash or am I missing something?

Use acid water , you should anyway as neutral water for sparging increases tannin ( potential haze forming) extraction....so they say.

I too read that thin mashes tend to make for drier beer. However I'm with Mysterio in that the type and behaviour of the yeast is going to make much more of a difference. I tend to mash thinner...it's just easier and more temperature stable.

"Ask 10 brewers and you'll get 11 opinions"

Cheers