How long of a mash is actually necessary?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk:

bgrubb7

Well-Known Member
Joined
Dec 7, 2007
Messages
138
Reaction score
1
Location
Effingham, IL
I always do 60 min mashes. I never do use an iodine test, but plan on getting some for next time. I read in John Palmer's site that the starches may be converted after 30 min, why continue the mash for another 30? Once the starches are converted to sugars, what else is there left to be done? I figure there has to be someone around here that can simplify an explanation for a dummy like me. :D
 

GilaMinumBeer

Half-fast Prattlarian
Lifetime Supporter
Joined
Jan 23, 2008
Messages
65,433
Reaction score
10,788
Once all the starches are converted it's done. I am just guessing here because it's been a long time since I've read into the chemistry of the mash but, it may be possible that the iodine test may not be a good indicator beyond a certain percentage of saccharide saturation. Perhaps there is a more complex breakdown of the sugars beyong the base starch conversion. That is, within the enzymatic rest target, the chains of sugars get broken down further and further into smaller chains that the targeted enzyme can handle.

Perhaps that. Oh and it gives you more time to prepare for the next step.

There are others that swear by even longer mashes too.
 

Jack

Well-Known Member
Joined
Aug 20, 2006
Messages
349
Reaction score
5
Location
Madison, Wisconsin
I've heard that the iodine test only tells you whether starches have been converted, and gives you no information about how many have been converted. From my lab experience, this seems about right because even very small amounts of sugars will react with iodine. You'd really want to measure gravity with a hydrometer or refractometer, I would think.

I know that some people only do 20-30 mashes, but I have to think that it hurts their efficiency numbers. I'll stick with a sixty minute mash until I am inspired to maximize my brewing efficiency.

Also, I believe that longer mash times (i.e. longer than 60 minutes) are only used when the saccharification rest temperature is <150 degrees F.
 

BierMuncher

...My Junk is Ugly...
Lifetime Supporter
Joined
Jan 17, 2007
Messages
12,440
Reaction score
937
Location
St. Louis, MO
Full conversion can be done in 20-30 minutes. A lot depends on the grain bill.

Mash time is not just about getting conversion, but affecting the attenuation once the beer is fermenting.

If you’re looking for a maltier beer that does not attenuate too dry, then a shorter mash is in order.

I started doing 90 minute mashes a while back (before I read up on this effect) and found that my identical recipes were no longer stopping at 1.012, but would go as low as 1.005.

Longer mash equals lower final gravity.
 

TexLaw

Here's Lookin' Atcha!
Lifetime Supporter
Joined
Sep 19, 2007
Messages
3,672
Reaction score
36
Location
Houston, Texas
When you're done, you're done. That's all there is to it. Once those starches are converted, you do not need to mash any longer. If that happens in 20 minutes, great. If it takes 60 minutes, so be it. The reason so many references say to do a 60 minute mash is because you can be virtually 100% certain that you will get full conversion after 60 minutes. That way, you can get by without an iodine test.

However, there is a downside to mashing longer than required. The enzymes are still working to make a more fermentable wort. The alpha amylase is still breaking down the forked chains into more linear chains, and the beta amylase is still chewing up the linear chains into maltose. So, if you mash longer than required to convert, then you may very well be losing mouthfeel that you wanted in the beer, increasing attenuation, and possibly throwing your beer out of the balance you wanted.

Whenever I hear a brewer say that he can tell no difference in his beer whether he mashes at 149 or 157, I ask him how long he keeps his mash working. Every time, it has been a brewer who mashes for 60 minutes, regardless, or does not perform an iodine test.

I always start checking for conversion around 30 minutes into the mash. For some recipes where I use very convertable grains, I might check after 20 minutes. My first test usually is just a taste test. If the mash liquor tastes starchy, I wait. If it tastes sweet, I check with the iodine test. If the iodine test shows full conversion, I start lautering.


TL
 
OP
bgrubb7

bgrubb7

Well-Known Member
Joined
Dec 7, 2007
Messages
138
Reaction score
1
Location
Effingham, IL
Quote from howtobrew.com:

"Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting."

----

So according to this, lets say that my iodine test shows full conversion after 30, then the rest of the time, I'm just converting unfermentable sugars to fermentable? Kind of defeats the purpose of higher mash temps if your looking for a maltier brew, right?
 

gonzo brewer

Well-Known Member
Joined
Jun 21, 2007
Messages
258
Reaction score
1
Location
Santa Clarita, CA
I started doing 90 minute mashes a while back (before I read up on this effect) and found that my identical recipes were no longer stopping at 1.012, but would go as low as 1.005.

Longer mash equals lower final gravity.[/QUOTE]

Great. I just brewed a Pliny the Toddler last night with a 75 min. mash and a 90 min boil using Safale 05. I'm hoping to get under 1.010 terminal gravity.

Wasn't quite sure why I was doing 75min mash.. but now I'm glad I did.

Perfect: A 5% dry IPA with 65 IBU, just in time for the hot summer.
 
OP
bgrubb7

bgrubb7

Well-Known Member
Joined
Dec 7, 2007
Messages
138
Reaction score
1
Location
Effingham, IL
Looks like I need to quit being cheap & lazy and get me some iodine. If I can shave a good 30 min off my brew day, then so be it!

Tex (and now BM), you answered my own question faster than I could post my own answer to my own question, :)
 
OP
bgrubb7

bgrubb7

Well-Known Member
Joined
Dec 7, 2007
Messages
138
Reaction score
1
Location
Effingham, IL
TexLaw said:
:mug: So did BierMuncher :D


TL
And now edited to reflect that. I just need to type faster so this doesn't keep happening to me:drunk:

So I guess to sum it up, it makes more sense (to me anyway) to stop mashing as soon as starches are converted. Then use your mash temps alone to determine your fermentability, rather than letting temps plus mash times determine this, since many times your mash length is only reversing any effect you gained by your higher mash temp.

Kinda explains why I keep mashing at higher temps, looking for a maltier profile that I can never seem to get in my final brew.
 

ajf

Senior Member
Lifetime Supporter
Joined
Oct 29, 2005
Messages
4,648
Reaction score
119
Location
Long Island
TexLaw said:
However, there is a downside to mashing longer than required. The enzymes are still working to make a more fermentable wort. The alpha amylase is still breaking down the forked chains into more linear chains, and the beta amylase is still chewing up the linear chains into maltose. So, if you mash longer than required to convert, then you may very well be losing mouthfeel that you wanted in the beer, increasing attenuation, and possibly throwing your beer out of the balance you wanted. TL
On the other hand, you could be reducing the excessive mouthfeel that you don't want, increasing the attenuation, and bringing the beer into the balance that you wanted. :)
I prefer Palmers description. "the brewer is working the mash conditions to produce the desired profile of wort sugars."
The only way to really know is to experiment to find out what you like.

Palmer also says "At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less." I believe that this should be "At a higher temperature, a stiffer mash or a higher pH, ..." as any of these factors will affect the conversion.

Another factor is the quality of the grain crush. Undercrushed grain takes longer to convert than well crushed or overcrushed grain.

Then there's the sparge method. If you fly sparge without a mash out, the enzymes will still be working their magic well into the sparge, whereas with a batch sparge, or mash out followed by a fly sparge, the effective mash time will be reduced.

Lastly, I can't possibly mash for less than 60 minutes because that's how long it takes me to heat the sparge water. :D

-a.
 

bradsul

Flyfisherman/brewer
Lifetime Supporter
Joined
Sep 12, 2006
Messages
4,889
Reaction score
42
Location
Ontario, Canada
ajf said:
... Lastly, I can't possibly mash for less than 60 minutes because that's how long it takes me to heat the sparge water. :D
Similar reasons I can't shorten my mash times. I need at least 35-40 minutes to get my sparge water to temperature, then I pull my mash out decoction and boil it. By the time I'm adding my decoction back into the main mash I'm usually at about 60-65 minutes.
 

TexLaw

Here's Lookin' Atcha!
Lifetime Supporter
Joined
Sep 19, 2007
Messages
3,672
Reaction score
36
Location
Houston, Texas
ajf said:
On the other hand, you could be reducing the excessive mouthfeel that you don't want, increasing the attenuation, and bringing the beer into the balance that you wanted. :)
I've found the opposite problem much more prevalent. Just about every brewer I've talked to, novice or expert, understands he can mash at a lower temperature to produce a thinner beer. However, I find many brewers that do not understand why their beers do not have more mouthfeel, even if they mash at 156-58F. That includes brewers who have been at it for years but never studied mash chemistry beyond "mash low for thin and mash high for thick" maxim. They end up packing their recipes with unfermentables when all they need to do is reduce their mash time.


TL
 

cactusgarrett

Well-Known Member
Joined
Apr 8, 2008
Messages
2,127
Reaction score
746
Location
Madison, WI
Is there an equation or calculation related to the OG and mash time? Can't imagine there would be, since it seems like a "brewing-by-feel" kinda thing.

But since i use BeerSmith it makes me wonder - do the brew programs take mash time into account into an OG value - and if so, how?
 

TexLaw

Here's Lookin' Atcha!
Lifetime Supporter
Joined
Sep 19, 2007
Messages
3,672
Reaction score
36
Location
Houston, Texas
There is no formula out there. Mashing is like cooking. You have to observe, learn, and apply. There are just too many things going on in a mash to make some predictive formula with any utility.

The brewing software products do not take mash time into account for either OG or target FG. For OG, they just look at the extract potential of the grain and whatever efficiency number you plug in. For target FG, they just look at the OG and the typical attenuation for the yeast. You, the brewer, have to adjust that on your own.


TL
 

Chad

Well-Known Member
Joined
Sep 15, 2007
Messages
1,026
Reaction score
12
Location
Apex, NC
I have to say that this has been one of the most helpful and informative threads in a while. I knew about mash temps but had no idea that mash time affected fermentability and body. Thanks, folks, especially Biermuncher, TexLaw & AJF. I appreciate it.

Chad
 

bradsul

Flyfisherman/brewer
Lifetime Supporter
Joined
Sep 12, 2006
Messages
4,889
Reaction score
42
Location
Ontario, Canada
This has me wondering if I should invest in a second burner just for handling decoction boils. This would let me start my mash out decoction as soon as conversion is complete. Though I definitely get significantly more mouthfeel when I mash high even with the overall mash time of ~60 minutes.
 

boo boo

Well-Known Member
Joined
Jun 6, 2005
Messages
4,164
Reaction score
46
Location
Hearts's Delight, Newfoundland
bgrubb7 said:
I always do 60 min mashes. I never do use an iodine test, but plan on getting some for next time. I read in John Palmer's site that the starches may be converted after 30 min, why continue the mash for another 30? Once the starches are converted to sugars, what else is there left to be done? I figure there has to be someone around here that can simplify an explanation for a dummy like me. :D
Starch is converted at different times with different PH levels and at different tempertures. Every one of these variables produce a different result in the mash. Even different malts require different lengths of time to fully convert.

Malt starch don't gelantinize until it reaches 149f. The conditions which produce the most fermentable wort start at a ph of 5.3 to 5.4 at a temp of 149f. A least fermentable wort is about 159f at a ph of around 5.7.

Reading out of Dave Millers book I see that " high mash tempertures favor alpha amylase and give a less fermentable wort. A high mash PH (5,7) also helps alpha amylase and gives a less fermentable wort. Short mash times give the amylases less time to break down dextrines and likewise give a less fermentable wort. To get maximun fermentability, these conditions must be reversed. Use a long, low-temperture mash schedule and set the ph around 5.3 But when working with high kilned malts, long mashes and low tempertures (150-153f) are needed.

Another factor influencing enzyme activity is the stiffness (thickness) of the mash. A thin mash- say 2.5 quarts of water per pound of grain- ultimately favors a more complete breakdown of carbohydrates in the kettle. However, because the enzymes are more diluted, breakdown takes longer to acheive. On the other hand, a stiff mash- around 1.33 quarts per pound, as I recommend-initially favors starch breakdown; however, as amylolysis proceeds, the increasing concentration of sugars in the mash inhibits further enzyme activity. A stiff mash also favors breakdown of protiens in the mash kettle, and provides one other benifit: it protects the enzymes better. At any given temperture, the thinner the mash, the faster the enzymes will be deactivated."

You have a lot of leeway to make the brew you want, and it takes a lot of practise to get it just right. But hey, we get to drink our mistakes.:)
 

balto charlie

Well-Known Member
Lifetime Supporter
Joined
Nov 17, 2005
Messages
888
Reaction score
45
Location
Md
So what happens to the guys that say they mash all through the night. I'm thinking they're going to have a very thin beer, no?? Excellent info here. I am book marking this thread for future study once I have all grain brew under my belt. I did get 2 kegs, soon off to the welder. Sounds likeI ialso should pick up a second burner! Thanks again folks....get back to work:D
Charlie
 

TexLaw

Here's Lookin' Atcha!
Lifetime Supporter
Joined
Sep 19, 2007
Messages
3,672
Reaction score
36
Location
Houston, Texas
balto charlie said:
So what happens to the guys that say they mash all through the night. I'm thinking they're going to have a very thin beer, no??
At some point, the enzymes just wear out and stop cutting, so you probably will have some unfermentables left. I always wondered about just how well you could predict that, though.


TL
 

blacklab

Banned
Joined
Nov 2, 2007
Messages
2,379
Reaction score
50
Location
Portland, ME
Wow, lots more moving parts here than I thought. Thanks everyone for the excellent explanations.
 

morrighu

Well-Known Member
Joined
Apr 29, 2008
Messages
53
Reaction score
0
Location
Dallas, TX
There are some amazingly good articles that go into all of this in excruciating detail, even by my standards.

http://homebrewandchemistry.blogspot.com/search/label/brewing serial

http://encyclopedia.jrank.org/BOS_BRI/BREWING_CHEMISTRY.html

And in case you've forgotten, maltose isn't the only thing you get from grains or mashing. Proteins are there too.

http://www.allaboutbeer.com/homebrew/proteins.html

And if you're interested in the water, here's a really good link to a technical analysis of it...

http://www.antiochsudsuckers.com/tom/brewingwater.htm

HTH,

M.
 

BeerCanuck

Well-Known Member
Joined
Sep 20, 2007
Messages
473
Reaction score
2
Location
St Catharines
Frankenstein drops into the thread..he loves the monster mash :drunk:

Good info HBT'ers

Cheers
BeerCanuck
 

OLDBREW

Well-Known Member
Joined
Oct 6, 2009
Messages
759
Reaction score
5
Location
SJ
then you add step mashing with time differentials between the two amylases enzymes, and you can customize your mash profiles even more. lots of room to experiment, um mm, sample, err, experiment.
 
Top