Is mash time critical?

[SwissRico]

So my brewing is improving and the evolution toward AG is moving ahead smoothly. Next brew day is Friday and I'm moving from steep, to doing my first proper partial mash, with a cooler as mash tun. I'm pretty sure on all my processes, but am wondering if there is a margin of error in the 60 minute mash time? I've searched HBT and find plenty on pH and temperature, but I haven't seen any posts saying "if you leave your mash for 90mins it'll taste like ..."

I'm not planning on leaving it for longer than an hour, but was just wondering...

 

[menerdari]

I have left my mash, for various reasons, longer than intended and my brews came out just fine.I would imagine there would be some limits but it certainly doesn't have to be to the exact second.
I actually screwed up on the amount of water in a mash once, way too little, made a thick soup, I ended up adding more and mashing the whole batch again, no problem, got a great tasting stout out of that one.

 

[blizz81]

There's a general consensus that longer mash time = more fermentable wort, but I've never been convinced this isn't more of a function of temperature loss / a lack of ability to maintain a consistent temp for however long you are mashing. This in and of itself could/would lead to a more dry beer.

 

[SwissRico]

Cheers guys. It is good to know that I can start my brew day with a quick clean of the essentials, get the mash mashing, and start my cleaning and prep for the boil whilst that's going on, without too much stress. Good to know!

 

[MaxStout]

Most of the conversion occurs in the first 20-30 minutes, then tapers off exponentially after that. It's critical to maintain mash temps during this first 20 minutes or so, but after that, not so much. The overall mash time isn't terribly important. There's a thread about 30 minute mashing. Just keeping that mash temp consistent in the beginning is key.

 

[brewkinger]

I've done mash times of 45min and checked for conversion and I've done mash times of 12hours.

Both resulted in exactly the beer that I set out to make with no noticeable bad effects.

The only critical time constraint is long enough for conversion to occur.

 

[FirstAidBrewing]

The only thing I'll add is that poorly crushed grain takes longer to convert so you may not be able to fully convert in a smaller time frame. A good crush negates that worry though

 

[dkeller12]

There is a recent thread discussing people speeding up their brew day by mashing in at night before bed and leaving it until morning to finish the brew day. Some tested it and it worked out well with no negative effects. So you are definitely not locked in at mashing for only 60 minutes. This was an extreme example but shows that many options exist.

 

[slym2none]

I have heard of people getting full conversion (or at least claimed to) at 10 mnutes out, but do you get good flavour extraction that way? Isn't the longer mash-time to get full-flavour out of your malts? Or does that happen in 10 minutes as well? (Hint: I think I already know the answer)

 

[Yooper]

Most of the conversion occurs in the first 20-30 minutes, then tapers off exponentially after that. It's critical to maintain mash temps during this first 20 minutes or so, but after that, not so much. The overall mash time isn't terribly important. There's a thread about 30 minute mashing. Just keeping that mash temp consistent in the beginning is key.

Yes, generally conversion does happen pretty quickly in well-modified malt.

I still go 60 minutes most often, just because while conversion may be finished, there are still some further modifications to the wort (some of the longer- chained sugars like maltotriose still being 'chopped' to smaller chained sugars) once the starch has been converted to sugar.

I sometimes go to 75 or 90 minutes when using a lot of adjuncts like unmalted grains, flaked corn or oats, even when I have plenty of diastatic power in there. It just ensures that there is still plenty of time to convert.

 

[ol-hazza]

Great article here which i read recently, its quite sciency in places but also has some great summaries and surprises (for me at least) like this one..

Heating a step mash over the top end of an enzyme’s range does not cause that enzyme to stop working instantly. It takes time for enzymes to denature. In some cases, enzymes will actually denature within their stated range. For example, at 149 °F (65 °C), beta-amylase is denatured within 40–60 minutes and alpha-amylase activity will cease after 2 hours at 153 °F (67 °C). The point is that, by changing mash temperatures, you are not cleanly switching enzymes on and off. Due to their simple mechanism of action, your control over them is much more “squishy.” (BYO Jan/feb 2008)

 

[Cyclman]

+1, I think most things brewing related are ranges, good-old-fashioned "bell curve" distributions. If your BMC, dealing with ranges is critical, as you need to optimize yield from your ingredients. For homebrewers, not so much.

 

[SwissRico]

Thanks for all the responses... HBT and you guys are fantastic!

 

[RM-MN]

I have heard of people getting full conversion (or at least claimed to) at 10 mnutes out, but do you get good flavour extraction that way? Isn't the longer mash-time to get full-flavour out of your malts? Or does that happen in 10 minutes as well? (Hint: I think I already know the answer)

Yes, if your grains are ground up really fine the conversion only takes 5 minutes or less but extracting the flavors takes longer. I've made two batches of beer with identical ingredients with one being mashed for 10 minutes and the other for 20. There definitely is more flavor in the 20 minute batch. I may do more batches with the 20 minute mash but I won't be recommending anyone else to do shorter than 30 minutes.

As the crush becomes coarser, the mash period goes up as it takes time to wet the particles through and more time yet to leach the resulting sugars out. Some people may need a 90 to 120 minute mash to accomplish full conversion/extraction.

 

[SwissRico]

After asking the question I found this nice article "How Long Should You Mash?"

"... In a single infusion mash, your goal is dissolve the starch granules from the malted barley, and allow the amylase enzymes to degrade the starch into simple sugars. The amount of time this takes depends on your mash temperature and the diastatic power of your malt."

 

[SwissRico]

...I sometimes go to 75 or 90 minutes when using a lot of adjuncts like unmalted grains, flaked corn or oats, even when I have plenty of diastatic power in there. It just ensures that there is still plenty of time to convert.

Thanks Yooper (yet again). But your answer got me thinking about my next brew, a American Brown that I'm spicing up for Christmas. Grain bill looks like this:

Belgian Biscuit 8%
CaraAroma 8%
Toasted Oats 6%
Munich II 31%
Amber LME 47%

It's going to be a malty/biscuity affair, and given the low diastic power of the Munich II, plus my oats, you have me thinking I should let it sit in the tun for a good 90mins. From what I read above it's certainly not going to do any harm, right?

 

[iBrewR]

It's going to be a malty/biscuity affair, and given the low diastic power of the Munich II, plus my oats, you have me thinking I should let it sit in the tun for a good 90mins.

If my source is right, Munich II has a diastatic power of 25, so it has a hard time converting itself. With the other grains mixed in, you may never get full conversion.

 

[SwissRico]

I'm waiting on a response from my LHBS on the diastatic power of the Munich II. If it is 20-25 °L could I look to go half and half with Maris Otter (120°L) ?

 

[DrWill]

There's a general consensus that longer mash time = more fermentable wort, but I've never been convinced this isn't more of a function of temperature loss / a lack of ability to maintain a consistent temp for however long you are mashing. This in and of itself could/would lead to a more dry beer.

If you mash hot you'll significantly denature your b-amylase so the reduction in temp won't yield a too much more fermentable wort (I think this is what you were referring to) so I would suspect time is the most important factor here. Of course there will still be plenty of active b-amylase so you could be right that this contributes to fermentability.

 

[Yooper]

I'm waiting on a response from my LHBS on the diastatic power of the Munich II. If it is 20-25 °L could I look to go half and half with Maris Otter (120°L) ?

Yes, or use 1 pound of 6 row (higher DP) in the mash. Munich II alone may not convert the oats.

 

[iBrewR]

I'm waiting on a response from my LHBS on the diastatic power of the Munich II. If it is 20-25 °L could I look to go half and half with Maris Otter (120°L) ?

Really depends on the Maris Otter. Crisp for instance only come in around 50L. Like Yooper says, 6-row would be good, but I'd probably just go with an American 2-row.

 

[SwissRico]

Thanks iBrewR. I was taking the 120°L from the beersmith blog. Seems MO is typically in the 50-70°L from what I've subsequently read... (I think that the Crisp number is a minimum). However after all the useful input from you guys I've toned down the crystal and oats added the MO and my average Diastatic power will now be 33. Still a little low but I will go for a thinner mash and 90mins in the tun. Still lots to learn!