Author Topic: What are the practical effects of mashing too low?  (Read 7154 times)

Offline Podo

  • Cellarman
  • **
  • Posts: 85
  • Korea
    • View Profile
What are the practical effects of mashing too low?
« on: December 09, 2009, 07:50:17 PM »
A couple weeks ago I made an Irish Red.  I was supposed to mash at 153 degrees, but I forgot to preheat my mash tun (sitting in my cold garage), and I got busy and didn't check the temperature while it mashed.  After an hour, I opened it and the mash was sitting at 141 degrees.  At that point, I didn't bother to see if it had converted, I just brewed it anyway. 

Can anyone predict how it might turn out?  I assume it will be very thin bodied, at least, but I wonder if it will even taste remotely alright.
So good once it hits your lips!

Offline Kaiser

  • Global Moderator
  • Senior Brewmaster
  • *****
  • Posts: 1797
  • Imperial Brewing Geek
    • View Profile
    • braukaiser.com
Re: What are the practical effects of mashing too low?
« Reply #1 on: December 09, 2009, 09:37:56 PM »
When you mash at a lower temperature the conversion process takes longer and may not complete in the 60 min that most of us give the mash. The result is lower efficiency and possibly unconverted starches that can give the beer a starch haze. If your mash temps are substantially lower (140 and lower) starch doesn't gelatenize and the conversion process takes much longer since the enzymes have to chew away on the outside of the ungelatenized starch granules. At this point you would have substantially lower efficiency.

Another effect is that enzymes like b-amylase and limit dextrinase survine much longer and are thus able to produce more fermentable sugars. The resulting wort will be more fermentable and the finished beer can end up thin and lacking body.

Kai

Offline ndcube

  • Brewmaster
  • *****
  • Posts: 612
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #2 on: December 10, 2009, 06:29:48 AM »
Another effect is that enzymes like b-amylase and limit dextrinase survine much longer and are thus able to produce more fermentable sugars. The resulting wort will be more fermentable and the finished beer can end up thin and lacking body.

Like my Belgians!  :)

Offline nyakavt

  • Assistant Brewer
  • ***
  • Posts: 104
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #3 on: December 23, 2009, 10:46:16 AM »
When you mash at a lower temperature the conversion process takes longer and may not complete in the 60 min that most of us give the mash. The result is lower efficiency and possibly unconverted starches that can give the beer a starch haze. If your mash temps are substantially lower (140 and lower) starch doesn't gelatenize and the conversion process takes much longer since the enzymes have to chew away on the outside of the ungelatenized starch granules. At this point you would have substantially lower efficiency.

A couple of online sources I've read say that barley starch gelatanizes between 147 and 153 F (64-67 C), but it can vary up to 10°C depending on factors like crush, modification, water to grist ratio, etc.  Ungelatanized starch has the consequences that Kai states above.  Based on my anecdotal experience of taking mash gravity readings on the last half dozen batches, just about any beer mashed in at or below 152 has not completed conversion in 60 minutes.  This is always remedied by raising up above 155 for a very short amount of time, maybe 5 min.  I theorize that ungelatinized starch is the main culprit, not sluggish enzyme activity, but either problem has the same solution.

Offline dean

  • Brewmaster
  • *****
  • Posts: 922
  • Me and Hayden, my newest grandson.
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #4 on: December 23, 2009, 11:13:57 AM »
When you mash at a lower temperature the conversion process takes longer and may not complete in the 60 min that most of us give the mash. The result is lower efficiency and possibly unconverted starches that can give the beer a starch haze. If your mash temps are substantially lower (140 and lower) starch doesn't gelatenize and the conversion process takes much longer since the enzymes have to chew away on the outside of the ungelatenized starch granules. At this point you would have substantially lower efficiency.

Another effect is that enzymes like b-amylase and limit dextrinase survine much longer and are thus able to produce more fermentable sugars. The resulting wort will be more fermentable and the finished beer can end up thin and lacking body.

Kai



Wow!  Short and sweet reply.  I think you answered a lot of my own questions about some problems I've had from time to time, thanks Kai.   8) 

Offline bo_gator

  • Assistant Brewer
  • ***
  • Posts: 124
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #5 on: December 23, 2009, 11:24:32 AM »


A couple of online sources I've read say that barley starch gelatanizes between 147 and 153 F (64-67 C), but it can vary up to 10°C depending on factors like crush, modification, water to grist ratio, etc.  Ungelatanized starch has the consequences that Kai states above.  Based on my anecdotal experience of taking mash gravity readings on the last half dozen batches, just about any beer mashed in at or below 152 has not completed conversion in 60 minutes.  This is always remedied by raising up above 155 for a very short amount of time, maybe 5 min.  I theorize that ungelatinized starch is the main culprit, not sluggish enzyme activity, but either problem has the same solution.

My name is Jeff and I am a low masher...it has been almost a week since my last low temp mash


My normal mash temp is 150*F, and I routinely go as low as 146*F. I always mash for at least 90 minutes when below 150*, but have never seen an unconverted mash, based on the iodine test. I wonder if this has something to do with the brand/type of grain being used?   
All views expressed in the above post are those of the author and do not necessarily represent the views of any other member of the AHA, BJCP, or home brew community at large.   


Home Brew’s curmudgeon at large

Offline dean

  • Brewmaster
  • *****
  • Posts: 922
  • Me and Hayden, my newest grandson.
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #6 on: December 23, 2009, 11:38:57 AM »
Hey Jeff, I just did an overnight mash two nights ago.  Mashed at 152F and left it overnight, when I got up it was still just over 100 F.  I boiled the wort that morning and left it to cool overnight as well... didn't use a chiller.  This morning when I got up it had a skim of ice on the top.   :o  :D  I had to warm it up to pitch yeast, and I have to say the wort is one of the best tasting worts I've made yet.  Now I'll just have to see how it finishes I guess.  I'm kinda chomping to try an open ferment too but I'm not that daring with my shed yet.   :D

Offline a10t2

  • Official Poobah of No Life.
  • *
  • Posts: 3155
  • Ask me why I don't like Chico!
    • View Profile
    • SeanTerrill.com
Re: What are the practical effects of mashing too low?
« Reply #7 on: December 23, 2009, 02:06:32 PM »
My normal mash temp is 150*F, and I routinely go as low as 146*F. I always mash for at least 90 minutes when below 150*, but have never seen an unconverted mash, based on the iodine test.

I think that's the main issue, really - not conversion, but whether or not the starches are gelatinizing. That wouldn't be shown by an iodine test.
Beer is like porn. You can buy it, but it's more fun to make your own.
http://seanterrill.com/category/brewing/

Offline Thirsty_Monk

  • Senior Brewmaster
  • ******
  • Posts: 1833
  • Eau Claire WI
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #8 on: December 23, 2009, 02:15:46 PM »
So what this test is good for?
Why it would not tell me if conversion is done?
Na Zdravie

On Tap At The TapRoom:
Bohemian Pilsner
Bohemian Dark Lager
Smoked Bock
MaiBock
American Brown Ale
Marzen
Root beer

Offline a10t2

  • Official Poobah of No Life.
  • *
  • Posts: 3155
  • Ask me why I don't like Chico!
    • View Profile
    • SeanTerrill.com
Re: What are the practical effects of mashing too low?
« Reply #9 on: December 23, 2009, 02:19:27 PM »
An iodine test will absolutely check for conversion of starches into sugars. What it won't tell you is if the starches have been completely extracted from the grains, which may not happen at very low mash temperatures.
Beer is like porn. You can buy it, but it's more fun to make your own.
http://seanterrill.com/category/brewing/

Offline dean

  • Brewmaster
  • *****
  • Posts: 922
  • Me and Hayden, my newest grandson.
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #10 on: December 23, 2009, 02:43:59 PM »
The IPA I just made came in almost 10 points lower than I expected and I did mash lower than I wanted, but I also had a high pH in the mash too.  I've also noticed that when I mash low, I've had haze, permanent haze not just chill haze as far as I can tell.  So Kai's reply explained a few things, for me anyway... and it didn't have a lot of chemistry lingo in it to confuse the hell out of me.   :D  ;)

Offline denny

  • Administrator
  • I must live here
  • *****
  • Posts: 11643
  • Noti OR [1991.4, 287.6deg] AR
    • View Profile
    • Dennybrew
Re: What are the practical effects of mashing too low?
« Reply #11 on: December 23, 2009, 03:48:49 PM »
FWIW, I've found the iodine test easy enough to screw up that I advise people to just skip it.
Life begins at 60.....1.060, that is!

www.dennybrew.com

The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

Offline bonjour

  • Administrator
  • Senior Brewmaster
  • *****
  • Posts: 1771
  • Troy, MI, 37mi, 60.9deg AR
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #12 on: December 23, 2009, 04:58:36 PM »
I can get an iodine test to say not converted on any mash I do, just have to do it wrong,  and that's real easy.

Fred
Fred Bonjour
Co-Chair Mashing in Michigan 2014 AHA Conference in Grand Rapids, Michigan
AHA Governing Committee; AHA Conference, Club Support & Web Subcommittees



Everything under 1.100 is a 'session' beer ;)

Offline Kaiser

  • Global Moderator
  • Senior Brewmaster
  • *****
  • Posts: 1797
  • Imperial Brewing Geek
    • View Profile
    • braukaiser.com
Re: What are the practical effects of mashing too low?
« Reply #13 on: December 23, 2009, 06:35:37 PM »
To present a different opinion, I recommend doing the iodine test. Especially when trying something new. If you do it on chalk, which is the method recommend, it is very easy to read. Here are some pics: http://braukaiser.com/wiki/index.php?title=Starch_Test

I'll have to rewrite this article to take out the method of using a white dish. Denny is correct that those test are difficult to read because of the husks and malt grits that may test positive.

Kai

Offline bluesman

  • Global Moderator
  • I must live here
  • *****
  • Posts: 8678
  • Delaware
    • View Profile
Re: What are the practical effects of mashing too low?
« Reply #14 on: December 23, 2009, 07:07:27 PM »
Agreed Kai. An iodine test is proof positive that starches were converted to sugar.

A refractometer can also confirm the presence of sugar in solution as well as precisely measure the %Brix. I believe it's all about time and temperature. When one follows the recipe protocol there's no need to test for conversion. It's time and temperature. All one needs is a calibrated thermometer and a timer. For example, If I mash at 150F for 60 minutes I will get conversion... it's that simple.

However, when the prescribed mash temp was not met it's a matter of either increasing the temp or increasing the mash time. As long as the mash temp was > 141F
Ron Price