Controlling Attenuation Through Mash Times

[BierMuncher]

I’ve read it before, but until recently I never thought it relevant to my brewing…the notion that your mash time will effect the attenuation (fermentability) of your wort.

I’m here to tell you it makes a huge difference. Recently I’ve taken to doing 90 minute mash times as a normal course. A few reasons:

• It seems to help my efficiency.
• My targeted OG’s seem more consistent and predictable.
• And just as important…it allows me time to go take a nap.

Now consider that I do a hybrid of a slow batch/fly sparge, and by the time I’m drained, my mash is easily sitting at prime conversion temps for nearly two hours. (Well within the safe window of preventing oxidation).

Since doing these longer mashes, I’ve noticed that my beers are over attenuating like crazy. Where one batch of Kona pale ale finished at 1.012 in December, my last (identical) batch finished at…1.005. Only difference was my mash time. It has just taken me a few batches (4 in a row) that came in under 1.010 to put 2 and 2 together.

To me, this is empirical evidence that longer mashes cause higher attenuation.

I like to brew lighter beers so this attenuation isn’t a big issue for my blondes, wits and other “crisp” beers. But for malty Pales, Octoberfests, Munich Helles, Ambers and English Ales, this could make the beers too dry for the desired style.

Between improving my efficiency using a batch/fly hybrid sparge, longer mashes and lower final gravities, I’m going to have to reformulate some of my recipes. My 4.5% beers are becoming 5.6% beers.

So…..

If you’ve been plagued by beers that just won’t drop below the 1.018 (ish) mark, try adding 20-30 minutes to your mash times and see if that helps. Or…if your big pale ales are just too dry and not malty enough, reduce your mash times by 20 minutes and see if that doesn’t produce more unfermentable sugars.

 

[RICLARK]

I like to brew lighter beers so this attenuation isn’t a big issue for my blondes, wits and other “crisp” beers. But for malty Pales, Octoberfests, Munich Helles, Ambers and English Ales, this could make the beers too dry for the desired style.

I am going to try this on my next batch and will report back, Do you think it will dry a German hefe out really bad?

 

[Beerrific]

I brewed a German Pilsner a few weeks ago that I wanted to finish very dry. I let the mash go at 147F for 90 minutes. I hit my targeted FG of 1.011 very easily. I would not hesitate to do the same thing for any beer that I am trying to get dry and/or no harm would come from even dropping a few extra FG points.

 

[WortMonger]

I've beed doing 75 minute 152*F mashes, as I like a little drier beer. Might have to give the 90 minutes a try and maybe mash at a higher temp as well for my less dry beers. This is good news as I thought I was going to take to long to do a decoction I was planning.

 

[foppa78]

I agree BierMuncher.
I also do 90 min mashes and believe that this in combination with a proper mash temperature will greatly aid in your attenuation level. If you are not worried about style and just want higher alcohol then you could do a 90 min mash at a lower mash temperature.
Now thanks to BierMuncher we might be seeing more druck posts!

 

[Kaiser]

Yes, time and temp have an affect on attenuation. That's why I recommend to pay attention to both. Contrary to my believe of the beta amylase having only a short life-span at mashing temps, I recently saw charts that suggest that it can easily be active longer than 60 min if the temp is around 150F.

If only the mash temp would not have such a big impact as well. Then we could control attenuation by mash time. This would be much easier to control than hitting the mash temp dead on.


Kai

 

[reshp1]

If only the mash temp would not have such a big impact as well. Then we could control attenuation by mash time. This would be much easier to control than hitting the mash temp dead on.


Kai

I don't want to get too off topic, but wouldn't doing a separate beta and alpha rest and varying the time spent in each also alleviate the need for spot on temperatures when controlling fermentability of wort? I started off doing this since I didn't really trust my thermometers (all read differently), but it doesn't sound like many people here do the two saccarification rest temps.

 

[jdoiv]

I don't want to get too off topic, but wouldn't doing a separate beta and alpha rest and varying the time spent in each also alleviate the need for spot on temperatures when controlling fermentability of wort? I started off doing this since I didn't really trust my thermometers (all read differently), but it doesn't sound like many people here do the two saccarification rest temps.

Yes, this works as well and is the way many of the larger breweries do it. The problem for homebrewers is that most use coolers for MLTs and would have to use infusions to raise the temp. This can be a bit tricky and more difficult than a single infusion mash where you simply change the time needed.

I have a SS MLT that is direct fired and have done several step mashes recently and have been getting better than rated attenuation lately. Luckily none have gone too dry yet.

 

[Funkenjaeger]

If you’ve been plagued by beers that just won’t drop below the 1.018 (ish) mark

Hrm, that sounds familiar. I think having an ordinary bitter finish at 1.017 was a sign that I need to take a closer look at my technique to figure out where the problem lies. Thanks to this thread I'll definitely be experimenting with mash times now.

 

[Ryanh1801]

I have been doing this on all my recent Belgium beers. My Trippel got 86% Attenuation, doing a 90 min mash.. My Belgian IPA I did a two hour mash on, we shall see how dry I can get it. My next attempt at a saison I will be doing an overnight mash.

 

[Piotr]

(Well within the safe window of preventing oxidation).

What do you mean by this oxidation...window?
How long is too long?

 

[Hermit]

What do you mean by this oxidation...window?
How long is too long?

bump since I'd like to see the answer to this question.

 

[ChillyP]

Originally Posted by Piotr View Post
What do you mean by this oxidation...window?
How long is too long?

Yes I'd like to have this clarified too.

 

[lamarguy]

Yes I'd like to have this clarified too.

Upstream (prior to pitching yeast) oxygen exposure has been over-hyped and shown to not be a problem in practice. This includes hot side aeration.

In fact, some argue that upstream oxidation is actually beneficial to beer flavor stability because the oxidized compounds are created earlier (rather than later) and removed as part of the hot/cold break and any remaining compounds are consumed by the yeast.

Consider Budweiser - they force sterile air through the wort after the boil is complete to remove undesirable volatile compounds (e.g., DMS, SMM, etc.). Clearly, this creates oxidation.

You should only worry about downstream (after the yeast is pitched) oxygen exposure to ensure good long term beer flavor stability.

 

[ChillyP]

Upstream (prior to pitching yeast) oxygen exposure has been over-hyped and shown to not be a problem in practice. This includes hot side aeration.

In fact, some argue that upstream oxidation is actually beneficial to beer flavor stability because the oxidized compounds are created earlier (rather than later) and removed as part of the hot/cold break and any remaining compounds are consumed by the yeast.

Consider Budweiser - they force sterile air through the wort after the boil is complete to remove undesirable volatile compounds (e.g., DMS, SMM, etc.). Clearly, this creates oxidation.

You should only worry about downstream (after the yeast is pitched) oxygen exposure to ensure good long term beer flavor stability.

See that's what I was told that I should only worry after.

 

[Jewrican]

i know i am pulling this from the graveyard, but i wanted to thank you for your recomendation.

I have been having an issue where beers wont come down far enough and i believe that this may be from having too many unfermentable sugars. I cant wait to try this out and am hoping that it makes a difference in my brewing.

 

[bigjoe]

I'll go ahead and comment since you woke it from the dead.

I haven't seen attenuation much beyond what the manufacture advertises, but I'm always on the high side of that figure or maybe 1-3% higher. I usually do longer mashes. I was doing step mashes on almost every brew and would start the clock on the rest once i reached the temp, which I didn't realize at the time was extending my mash. I did a few single infusion mashes and got poor efficiency, but decent attenuation. It didn't dawn on me right away that it was longer mash times giving me the extra points in efficiency. What made me realize what was going on was doing an iodine test after a few batches that I had very poor efficiency on. I do this on every batch now as well as check pH at about 15 minutes into the mash.

 

[Sevenal]

These old threads are priceless.
I just ran a 6 lb grain mash to produce 3 gallons of beer.
Decided to experiment, so along with the dregs of misc. grain around the house for a total grain bill under 7 lb and 4 oz of molassas and 2 oz DME, I hit a 1.05 OG
This way
1 hour 153 degree F mash followed by a trickle wort transfer to my boil pot of another 60 min. 2.5 gallons of water to start with.
A secondary mash out of 159 degree F with roughly 1.5 gallons of water for 60 min and another trickle transfer followed by a 75 min boil.

I used a washed S-04. Its been in the 3 gal carboy for 6 days and Im betting it gets really dry.

 

[BierMuncher]

These old threads are priceless...

Who you calling old???

 

[opiate82]

I'm glad this got re-necro'd. I was always finishing up a little higher than expected, but I had just assumed it was because I wasn't using a yeast starter. While I am going to start using a starter, I will also keep the thoughts here earmarked in my brain as I slowly work on nailing down my methods.

 

[catdaddy66]

Subscribed! Need this info as I begin the All Grain Odyssey!

 

[CA_Mouse]

I have begun doing my mashes for longer times after reading this and a comment from Denny about mashing for 90 mins @ 148F for a drier Belgian. I have started adjusting my times to 75 mins for some of my drier stouts and lowering the mash temp slightly, everyone loves them. I use shorter times and higher temps for Pales and anything that needs to be a bit sweeter.

Mouse

 

[grathan]

I wonder if a temperature drop is responsible for drier beer. The higher mash temp breaks the protein down for the lower temp amylase. So when it reaches the lower temps they have a feeding frenzy on the already broken down protein chains.

 

[JohnEvens]

I have recently started brewing all grain. I am about 5 brews in. At first my efficiency wasn't that great, but now I am hitting 70-75% efficiency. I am now also having a problem with over attenuation.

I have been doing 60 min mashes at about 150F, but to get the improvement in efficiency I have been doing quite slow fly sparges. Although my sparge water is about 180F, I feel like the grain temp doesn't really increase as the addition rate is slow and with the lid being opened often I think any additional temperature is lost. I don't do a mash out step.

So, I feel like my sparge is basically an extension of the mash at about the same temp. It takes at least 30 mins to complete the sparge.

Any tips on what to do?
Add a mash out to get the temp up?
reduce the mash time?

The other issue is that I have designed my last few recipes thinking that my efficiency wouldn't be that great, so maybe if I design them with the right efficiency, the ratio of base malt to specialty malts will be different and I will get a higher finishing gravity?

 

[Hermit]

I have recently started brewing all grain. I am about 5 brews in. At first my efficiency wasn't that great, but now I am hitting 70-75% efficiency. I am now also having a problem with over attenuation.

I have been doing 60 min mashes at about 150F, but to get the improvement in efficiency I have been doing quite slow fly sparges. Although my sparge water is about 180F, I feel like the grain temp doesn't really increase as the addition rate is slow and with the lid being opened often I think any additional temperature is lost. I don't do a mash out step.

So, I feel like my sparge is basically an extension of the mash at about the same temp. It takes at least 30 mins to complete the sparge.

Any tips on what to do?
Add a mash out to get the temp up?
reduce the mash time?

The other issue is that I have designed my last few recipes thinking that my efficiency wouldn't be that great, so maybe if I design them with the right efficiency, the ratio of base malt to specialty malts will be different and I will get a higher finishing gravity?

150 will give you a highly fermentable wort to start with. You could try a yeast with lower attenuation. Also, if you don't raise the grain bed to 168/170 before you start sparging then the stuff drained to the kettle will continue to 'mash'. I've been thinking of just adding my non-fermentables 'up front' depending on the recipe. Some with high levels of crystal will have a lot of non fermentables anyhow. Perhaps a bit of dextrin malt for those without a lot of other non-fermentables?

 

[jmf143]

In addition to mash duration having an effect on fermentability / attenuation, one needs to take mash thickness into consideration.
Thin Mash (>2qts/lb)
- increases fermentability
- increases attenuatioin
- increases the time it takes for conversion

Thick Mash (< 1.25qts/lb)
- decreases fermentability
- increases body
- can do "bigger" beers as more grain fits in mash tun
- can sparge with more water which may increase efficiency

 

[ArcLight]

Where did you read that it's beneficial to introduce O2 during the mash?
Can you site some sources or papers?

Upstream (prior to pitching yeast) oxygen exposure has been over-hyped and shown to not be a problem in practice. This includes hot side aeration.

In fact, some argue that upstream oxidation is actually beneficial to beer flavor stability because the oxidized compounds are created earlier (rather than later) and removed as part of the hot/cold break and any remaining compounds are consumed by the yeast.

Consider Budweiser - they force sterile air through the wort after the boil is complete to remove undesirable volatile compounds (e.g., DMS, SMM, etc.). Clearly, this creates oxidation.

You should only worry about downstream (after the yeast is pitched) oxygen exposure to ensure good long term beer flavor stability.

 

[LovesIPA]

Where did you read that it's beneficial to introduce O2 during the mash?
Can you site some sources or papers?

Where did he say that it was beneficial to introduce O2 during the mash?

 

[chad_]

I have a couple questions. First is there any down sides to doing a longer mash and having the mash temp drop below 148 F?

Secondly,

Thin Mash (>2qts/lb)
- increases fermentability
- increases attenuatioin
- increases the time it takes for conversion

Thick Mash (< 1.25qts/lb)
- decreases fermentability
- increases body
- can do "bigger" beers as more grain fits in mash tun
- can sparge with more water which may increase efficiency

I see how these would affect the beer in the ways you stated, but how could you achieve the same O.G. with both these methods? I feel like you will always have a greater O.G. with the thick mash. Would you have to boil the thin mash longer to achieve the O.G., but wouldnt this also affect the fermentability?

Thanks,
Chad

 

[ArcLight]

Chad,
If you compare two batches, batch 1 is mashed at 148 for 180 minutes, while batch 2 is mashed at 156 for 60 minutes, batch 1 will be more fermentable and reach a lower final gravity. But they may both have the same original gravity, assuming the alpha amylase has time to break the long chain molecules. Since Alpha Amylase is slower acting below it's optimum temperature, it may take longer (thus I made up 180 minutes).


The "downside" of the lower mash is a thinner beer as more alcohol is produced as there is more the yeast can digest. That may or may not be what you are after.

I have a couple questions. First is there any down sides to doing a longer mash and having the mash temp drop below 148 F?

Secondly,



I see how these would affect the beer in the ways you stated, but how could you achieve the same O.G. with both these methods? I feel like you will always have a greater O.G. with the thick mash. Would you have to boil the thin mash longer to achieve the O.G., but wouldnt this also affect the fermentability?

Thanks,
Chad