Effects of longer mash times

Anyone have a good resource or straight up answer for what happens when you leave your mash in the tun for longer than 60 mins?

As a general rule, I mash at 65 mins. just to have a couple mins insurance. I don't do iodine test, but hey it taste sweet. I'm wondering will there be any continued effect of the bier chemistry which would cause head retention, mouthfeel, fermentability, etc. issues? I know 5 mins shouldn't have an effect, but what if someone mashed for 80, 90, 120 mins?

Schlante,
Phillip

I'd like to know this as well. I have a brew coming up with a rest at 149F. That seems awful low to me, so I've been considering mashing a little longer just for good measure.

One thing I do is start recirculation before my mash time is up. You're not loosing heat and it cuts back on time.

I usually mash for 60 minutes at 152 - 154 with a thick mash (1 qt per lb). This results in complete conversion, and a fairly dextrinous wort. I have checked the process of the mash with a refractometer, and found that with my crush (and the temp and thickness mentioned above) I get complete conversion after 40 - 50 minutes.
If I continued such a mash beyond 60 minutes, I would think (but have never verified) that the dextrines would be broken down more, resulting in a more fermentable wort
.
On the rare occasions that I mash at lower temps (< 150), I usually mash thinner (1.25 qts per lb) and for 90 minutes. I have found that I did not get complete conversion at 60 minutes, and Dave Miller recommended a longer mash under those circumstances.

-a.

go read howtobrew or tcjohb section on the enzymes in the mash.

How to Brew - By John Palmer - The Starch Conversion/Saccharification Rest

In short a low temp is going to favor the beta amylase which chops away at the ends of the chains one by one taking a long time, but can end up with more single glucose molecules.
A high temp with favor the alpha amylase which cuts the dextrins in half which ends up with more high chain sugars and dextrins left over but a faster conversion.

If you're an AG brewer that makes your own recipes you should really understand this along with the chemistry of your water profile and while your at it mash pH. Also some of the different rest temps and how the enzymes at those temperatures work. This stuff is very important to the taste, mouthfeel, how clear etc etc your final product is. Well it's a start anyways.

But hey some people don't care that much. I brew to make the best beer I possibly can though.

A longer mash time can improve the efficiency and will also improve the fermentability b/c you are giving the enzymes more time to work. Depending on your other mash parameters (temp, crush, water/grist ratio, diastatic power, pH) there will be a minimum time that you'll need to get sufficient conversion and your desired fermentability. In general, the higher the rest temp, the shorter it takes to convert the mash as the enzymes work better at higher temps. But because beta amylase is quickly denatured at temps above 150F, you may not be able to mash at a higher temp unless you are ok with poorly fermentable wort. Pale malts generally have enough diastatic power to reach conversion after 20-30 min at temps around 154F. But most brewers settle on 60 min as you may have to change the temp if you change the mash time to get the same fermentability. As a result it is just much easier to keep the time constant and play with the temperature. Only if you mash at a temperature so low or a grist so weak in diastatic power that you don't get conversion after 60 min would you then extend the mash to 90min or longer.

Kai

z987k said:

go read howtobrew or tcjohb section on the enzymes in the mash.

How to Brew - By John Palmer - The Starch Conversion/Saccharification Rest

In short a low temp is going to favor the beta amylase which chops away at the ends of the chains one by one taking a long time, but can end up with more single glucose molecules.
A high temp with favor the alpha amylase which cuts the dextrins in half which ends up with more high chain sugars and dextrins left over but a faster conversion.

If you're an AG brewer that makes your own recipes you should really understand this along with the chemistry of your water profile and while your at it mash pH. Also some of the different rest temps and how the enzymes at those temperatures work. This stuff is very important to the taste, mouthfeel, how clear etc etc your final product is. Well it's a start anyways.

But hey some people don't care that much. I brew to make the best beer I possibly can though.

Click to expand...

I do understand the differences, if not the nuances, of beta and alpha amylase and the optimum temps at which both operate. Oddly enough I was browsing through the online edition of How to Brew and thinking about mashing while my wort was cooling, that's what spawned the question. I too am interested in only making the best beer possible, otherwise I wouldn't be asking such questions to further my understanding of mash dynamics. Also I trust that my water chemistry is such that I'm getting full conversion so I forego the iodine tests. But I am also very interested in the economics and time expenditures as I have family obligations far more important than good bier. That's what got me to thinking about it, what happens if I'm side tracked by a sick kid or some such and don't get to my mashout until 2 hours later!!!

Kaiser said:

A longer mash time can improve the efficiency and will also improve the fermentability b/c you are giving the enzymes more time to work. Depending on your other mash parameters (temp, crush, water/grist ratio, diastatic power, pH) there will be a minimum time that you'll need to get sufficient conversion and your desired fermentability. In general, the higher the rest temp, the shorter it takes to convert the mash as the enzymes work better at higher temps. But because beta amylase is quickly denatured at temps above 150F, you may not be able to mash at a higher temp unless you are ok with poorly fermentable wort. Pale malts generally have enough diastatic power to reach conversion after 20-30 min at temps around 154F. But most brewers settle on 60 min as you may have to change the temp if you change the mash time to get the same fermentability. As a result it is just much easier to keep the time constant and play with the temperature. Only if you mash at a temperature so low or a grist so weak in diastatic power that you don't get conversion after 60 min would you then extend the mash to 90min or longer.

Kai

Click to expand...

Kai

As I stated to z987k I have a basic understanding of the different enzymes and at what temps they work at etc. This question isn't really intended to address any problem I'm having, just a point of discussion. My understanding is much as you put it, that on an average mash at 152F conversion is generally complete within about 30 mins.

My understanding is also that there is no going back so to speak when mashing. The nature of enzymes is such that once the effective operating temperature range is surpassed/bypassed there is no possibility for that enzyme to have any activity, thus the sweet spot of 150-155 for the average homebrew mash. FWIW I've found I get good solid fermentability, mouthfeel, and head retention when mashing at 151-152. My mashings at 154-156 have produced a far to unfermentable wort and thin BAD head retention.

I guess the reason I'm asking this question is that from my understanding additional time even 30 mins in the mash wouldn't seem to be a problem because all the available enzymatic activity has already taken place. Thus I'm wondering if any DAMAGE could be done with a prolonged mash. I'm also curious to know what would happen if you began a mash at say 153F and it gradually fell so that at the end of 90-120 mins it were at something like 146-147. As the carbohydrates have already been converted to sugars at a higher temperature, I would think the wort would retain the properties of the 153F mash rather than being made more fermentable because it drifted to lower temps once conversion had occured!? Or am I wrong, could the more complex sugars produced at 153F continue to be broken down to simpler sugars at 147F?

In conclusion I suppose what I'm asking is since conversion would already have taken place would a prolonged mash have any effects either good or bad?

Schlante and thanks for the discussion,
Phillip

ajf said:

I usually mash for 60 minutes at 152 - 154 with a thick mash (1 qt per lb). This results in complete conversion, and a fairly dextrinous wort. I have checked the process of the mash with a refractometer, and found that with my crush (and the temp and thickness mentioned above) I get complete conversion after 40 - 50 minutes.
If I continued such a mash beyond 60 minutes, I would think (but have never verified) that the dextrines would be broken down more, resulting in a more fermentable wort
.
On the rare occasions that I mash at lower temps (< 150), I usually mash thinner (1.25 qts per lb) and for 90 minutes. I have found that I did not get complete conversion at 60 minutes, and Dave Miller recommended a longer mash under those circumstances.

-a.

Click to expand...

That's interesting ajf. If I recall properly from a recent episode of basic brewing the jist was that a thinner mash helps effeciency when mashed at 90 mins. But thier definition was thinner than 1.25 qts/lb. I believe they were mashing at closer to 1.75 qts/lb... but then again maybe I have it all wrong, the codine based cold medicine is getting too me about now! I know Palmer and others advocate 1.25 qts as a default, and that's what I shoot for.

Oh yea I also think of Alf everytime I see your username!

Schlante,
Phillip

MVKTR2 said:

I know Palmer and others advocate 1.25 qts as a default, and that's what I shoot for.

Click to expand...

But what if John is wrong on this? What are his arguments why such a thick mash is the best for *ALL* beers? I had been bringing up the benefits of a thin mash in my interview with Basic Brewing. My experience has been that thinner mashes work better and may also give a significant efficiency boost. They are traditional for English beers and that's where they are best used today.

As for the distraction from kids and family live, I hear you very well. The fact is that the most gains in efficiency and attenuation potential are made during the first 30 min of the mash. As a result the difference between a 60 and a 90 min mash should not be really dramatic. If you have to let the mash sit for 90 min instead of 60 min, just let it sit longer. But make sure to take a note of it in case you notice a difference in the outcome.

Kai

Kaiser said:

But what if John is wrong on this?

Click to expand...

I may have been a bit quick here. In the latest edition of How To Brew he actually advocates a mash between 1.5 and 2 qt/lb (3-4 l/kg) which I have been advocating as well.

Kai

Kai since I have your ear, may I ask a few questions based on your experiment pdf from basic brewing?

1A) If I read your charts correctly a higher temp mash say 156F produces a greater extraction/conversion rate than say a 149F mash, correct?
1B) But due to the fact that it is converting carbs into larger less simple sugars it is significantly less fermentable/posesses less maltose?
1C) A mash at 149 would extrct/convert less sugars than a higher mash temp, but will provide greater fermentability?

2A) If the above is correct am I right in assuming that to achieve the greatest brewhouse effeciency possible it would be best to mash at 149F (beta amylase) for the first 30 mins of mash, then to raise the temp to 155F (alpha amylase) for the remaining 30 mins to get a higher extraction/conversion rate?
2B) Also performing this task would be a logical step in producing good mouthfeel & head retention, would it not?(this question assumes ph, equipment, etc. are all working properly)

This I find very interesting as I've been very happy to mash at 152, what I refer to as splitting the difference, and I'm set at 71-72% brewhouse effeciency. Let it be known I batch sparge in a 5gal round cooler with braided hose, which would limit my eff. to varying degrees. I'm assuming if I started mashing in the way I laid out in point 2 my effeciency might rise a few points. Is that probable, would a simple step mash focusing on beta and alpha amylase raise my eff. a few points and add mouthfeel, head retention etc.

May I say that I settled on the sweet spot of 152F as my brewhouse mash target for standard biers due to my experience with mashing at 154-156 for a couple of low alc. mild and stouts trying to maintain mouthfeel. All I wound up with was a VERY thin head and middle of the road mouthfeel (at best).

Finally let me thank you for your helpful resource. I must ask was this some sort of thesis project, or purely a hobby driven experiment?

Schlante,
Phillip

I'll be away for 2 days and will answer when I come back.

Kai

I have always done 60 minute mashes, until I brewed up stones vertical epic 08.08.08, which called for a 148F mash for 120 minutes. Turned out great! A highly fermentable wort that finished very dry. Since then, If I'm mashing under 150F, I do 120 minute, otherwise, I stick to 60-70 minutes. Seems to work well for me.

I'm still waiting to hear (read) about possible damage caused by prolonged tail off in the temps (ie the situation when you have to run away for 4 hours to do something very important and the mash just sits there cooling down) I know that sometimes a longer mash is advocated not for saccarification but for colour extraction when brewing with very roasted malts. Would excess tannin extraction be a problem - for instance for a 4 hour mash??

giligson said:

I'm still waiting to hear (read) about possible damage caused by prolonged tail off in the temps (ie the situation when you have to run away for 4 hours to do something very important and the mash just sits there cooling down) I know that sometimes a longer mash is advocated not for saccarification but for colour extraction when brewing with very roasted malts. Would excess tannin extraction be a problem - for instance for a 4 hour mash??

Click to expand...

Tannin extraction is a byproduct of mash or sparge heat becoming too high, experienced during the mash/sparge when heating the grain bed to above 170F. It's a byproduct of heat, not time.... atleast that's what I was told!

Also extraction of tannins can happen when sparging the grain bed too much. If the brewer continues collecting wort when the run off has reached 1.009 or less, tannins will be extracted. (I've read text that says 1.010 is the point which tannins are extracted and other text saying the sparge is safe from tannin extraction to a point as low as 1.008, so I split the difference).

I know that's not an answer of your question, but to my knowledge that's the most important nuggets of knowledge concerning tannin extraction from a grain bed. As for your question, it's a good one and I'm not sure either of us will get an answer about the effects of prolonged mash cycles with or without temp loss. I'm not aware a set of experiments having been conducted which would yield a scientific answer.

Schlante,
Phillip

MVKTR2 said:

I'm not aware a set of experiments having been conducted which would yield a scientific answer.

Schlante,
Phillip

Click to expand...

Why not do one?
Same basic mash keep it simple
2 row and maybe 40L or something like that
#1 @ 150-152* for say 60 min
#2 @ 150-152* for say 4 hours

Bitter neutral and low say in the 20-25 IBU
Take hydro samples of each throughout the process
make sure they are brewed on the same day and ferment together
Just an idea
JJ

MVKTR2 said:

Tannin extraction is a byproduct of mash or sparge heat becoming too high, experienced during the mash/sparge when heating the grain bed to above 170F. It's a byproduct of heat, not time.... atleast that's what I was told!
Schlante,
Phillip

Click to expand...

I thought the temperature threshold was closer to 180F. Many of the guides I have been reading suggest 170-175 for the sparge.

noisy123 said:

I thought the temperature threshold was closer to 180F. Many of the guides I have been reading suggest 170-175 for the sparge.

Click to expand...

I'm going from memory, as I was last night, so you could be correct, and you've now got me questioning myself! My understanding is that you don't want to go beyond 170F, though a little higher doesn't hurt. Tannins are actually extracted when a grain bed reaches a gravity of 1.019, but it doesn't become really accelerated until something like 1.008, thus most homebrew text use 1.010-1.008 as a base line to quit sparging, I suspect the same is true of the 170F reference and people are just adding some padding to help us haphazard homebrewers! The reason most text suggest a sparge water of 180F (or more) is because the grain bed is generally sitting at about 150-155F. If one sparges with 170F water, due to thermal transfer between the grain mass and water mass one would not come close to raising the temp to 170, I know from experience! For this reason it's best to actually add water at or above 180 degrees to raise the sparge temp for more eff. sparging. My research is based almost solely on batch sparging which has a little different dynamic compared to fly sparging.

The fly sparge process creates an imbalance through the the grain bed with the top of the grains being more diluted (having sugars extracted at a faster rate, resulting in a lower gravity, aiding in tannin extraction) and the bottom of the grain bed being less diluted (having more sugars present). This imbalance combined with the grain bed having a higher temp at the top vs the bottom in a fly sparge process creates an easier scenario for tannin extraction. Fly spargers don't beat me over the head if I didn't get that just right, by that's as simple as I can describe it based on the text I've read.

Schlante,
Phillip

Jaybird said:

Why not do one?
Same basic mash keep it simple
2 row and maybe 40L or something like that
#1 @ 150-152* for say 60 min
#2 @ 150-152* for say 4 hours

Bitter neutral and low say in the 20-25 IBU
Take hydro samples of each throughout the process
make sure they are brewed on the same day and ferment together
Just an idea
JJ

Click to expand...

While it's just an idea, I think it's a good un! But I don't have time to try it right now... any other takers?.... Jaybird perhaps?

Schlante,
Phillip

Ps Jaybird, I love 'Bleeding Cowboy' font used in some of your brewery logo/labels, you can't design a bad label with it! We're using it for our homebrew club logo.

Kaiser said:

I'll be away for 2 days and will answer when I come back.

Kai

Click to expand...

Where are your priorities...J/K
I think this may mean the end of the 5 gallon MLT. I may be off to HD for a new cooler. I too, anxiously await your reply. Charlie

balto charlie said:

I think this may mean the end of the 5 gallon MLT. I may be off to HD for a new cooler. I too, anxiously await your reply. Charlie

Click to expand...

I don't think you need to retire the cooler MLT for this. I still use mine and don't see these problems.

The graphs from the experiment are a little misleading when it comes to the achievable efficiency. Yes, conversion will happen faster at higher temps, but higher temps are not necessarily necessary for full conversion. I explained that here: Understanding Efficiency - German Brewing Techniques

The idea is that there should be enough enzymatic power in the mash that you can reach a point of saturation (where no more or only little starches are left for conversion) This point will be reached earlier with a higher temp than with a lower temp, b/c the a-amylase works quicker at higher temps. But that may not matter if both temperatures reach this point before 60 min. You may also extend the time of the rest if using a rest temp below 150F. But to reach this point of saturation, the other mash parameter will have to be optimal enough.

While mashing at 145 and then at 160 for full conversion is exactly what German brewers do, you need to keep in mind that if there is a significant gain of conversion efficiency at 160F, it will be in the form of poorly fermentable extract and lowers your attenuation potential. But for a typical German beer with 80% attenuation a 30-45 min mash at 63C and then 30 min at 70C works well (at least for me).

WRT to the maximum temp of the mash for lautering, I have found (in the literature) that the limit of 170-180 is not set by the sudden extraction of tannins, but by the desire to keep the a amylase active during lautering active as it is needed to convert any rouge starches that are released during this process. I know this goes against the widely accepted knowledge that mash-out kills *all* enzymes, but this makes more sense to me and I have also shown that a mash-out does not kill all enzymes. There have been some heated debates on this on the NB forum.

Longer mash times and higher mash temps increase the tannin extraction, but there is not a sudden jump at 180F. It's more about the pH then the temperature.

Kai

Kaiser said:

I may have been a bit quick here. In the latest edition of How To Brew he actually advocates a mash between 1.5 and 2 qt/lb (3-4 l/kg) which I have been advocating as well.

Kai

Click to expand...

When I was talking about the 5 gallon MLT I was referring to using 2 qts/lb. I max out my 5G cooler at 12 lbs grain w/ 1.25qts. water. How are you able to mash this much grain using 2qts water in a 5 G MLT?

Kaiser said:

I may have been a bit quick here. In the latest edition of How To Brew he actually advocates a mash between 1.5 and 2 qt/lb (3-4 l/kg) which I have been advocating as well.

Kai

Click to expand...

I heard this and saw the video podcast with the rye pale ale where he mashed at 2 qt /lb and got a serious efficiency boost. I normally have been doing 1.25 qt /lb, looking back on my notes when I have "erred" by going higher my beers tasted better.

I will now intentionally repeat my last recipie done at 1.25 and try it at 1.75 for comparison.

Kaiser said:

I don't think you need to retire the cooler MLT for this. I still use mine and don't see these problems.

The graphs from the experiment are a little misleading when it comes to the achievable efficiency. Yes, conversion will happen faster at higher temps, but higher temps are not necessarily necessary for full conversion. I explained that here: Understanding Efficiency - German Brewing Techniques

The idea is that there should be enough enzymatic power in the mash that you can reach a point of saturation (where no more or only little starches are left for conversion) This point will be reached earlier with a higher temp than with a lower temp, b/c the a-amylase works quicker at higher temps. But that may not matter if both temperatures reach this point before 60 min. You may also extend the time of the rest if using a rest temp below 150F. But to reach this point of saturation, the other mash parameter will have to be optimal enough.

While mashing at 145 and then at 160 for full conversion is exactly what German brewers do, you need to keep in mind that if there is a significant gain of conversion efficiency at 160F, it will be in the form of poorly fermentable extract and lowers your attenuation potential. But for a typical German beer with 80% attenuation a 30-45 min mash at 63C and then 30 min at 70C works well (at least for me).

WRT to the maximum temp of the mash for lautering, I have found (in the literature) that the limit of 170-180 is not set by the sudden extraction of tannins, but by the desire to keep the a amylase active during lautering active as it is needed to convert any rouge starches that are released during this process. I know this goes against the widely accepted knowledge that mash-out kills *all* enzymes, but this makes more sense to me and I have also shown that a mash-out does not kill all enzymes. There have been some heated debates on this on the NB forum.

Longer mash times and higher mash temps increase the tannin extraction, but there is not a sudden jump at 180F. It's more about the pH then the temperature.

Kai

Click to expand...

Thanks for this info. Lots of good stuff in your link. That's your page? Very nice. Charlie

balto charlie said:

Thanks for this info. Lots of good stuff in your link. That's your page? Very nice. Charlie

Click to expand...

Thanks. Yes this is my page. I wanted a place where I could summarize all the experience that I have gathered in my own brewing and the literature regarding efficiency.

Kai

Kai

It'd be great if you could take a look at post #10 and look at some of the questions there.

Also, and more imporantly to me and I suppose all of us, I'd like to run a scenario past you to help us understand the expected results from a thinner mash.

*Note I haven't run all the numbers here, and am guestimating a Scottish/Scotch recipe.

Assuming the brewer is using a 5 Gal. MLT(& that 12-12.5#'s grains plus 1.25 qts water per pound yields the total capacity), what would be the difference between mashing:
11.375# Marris Otter
1# Crystal 60
.125# Roasted Barley
12.5 #grist + 1.25 qts water = 22 qts. (5.5 gallons)
From experience I know if I brew the bier above I'll get 72% efficiency resulting in:
1.061 O.G. for a 5.5 Gallon batch or
1.085 O.G. for a 4 Gallon batch

What happens if I modify the recipe above to mash in the same 5 gal. MLT with 2 qts of water per lb.? My estimation on the grist volume is a total of 8.55#'s grain thus the recipe would be modified as follows.
8.55 # plus 17.1 quarts of water would give me 22 qts volume.
7.78# Marris Otter
.68# Crystal 60
.09# Roasted Barley
What should the brewer's expected efficiency be with this recipe and a change to 2 qts. per lb in the mash?

•Note if it's 80% eff. my OG for 5.5 gals. would be 1.047

Schlante,
Phillip

Traditional British style infusion mashes are with about 2-2.5 l/kg (1 - 1.15 qt/lb) very thick

the maths looks a bit suspicious here.....

I have just one bit of purely anecdotal evidence to provide here. A couple of years ago, I was brewing a Saison and I got called away on an emergency in the middle of my mash which was sitting in a sealed cooler. I didn't get back to it until early the next morning. So, effectively, my mash was slowly freefalling over a period of about 18 hours. When I opened it up, it was just under 60°C. It had started at around 67°. It fermented out just fine with no off flavours or any signs of souring. It did ferment very dry, but I was expecting that given the yeast strain that I was using, but this may have been exacerbated by the extremely long mash.

I'm not sure that there is much to conclude from this, but I figured I would throw it out there anyway.

I usually mash for 90 minutes.

I had T-58 attenuate more than the specs sheet, which says 70%. I usually get between 75 and 81%, this is regardless of the mash temp. I use sugars in the boil.

S-04 attenuates between 77 and 83% for me, and this is mashing high at 154.4F with a simply grain bill of Pilsner, Wheat and flaked adjuncts and sometimes a lighter crystal.

Wyeast 1318: used 2 times--- mashed at 154.4F both times and the attenuation was 79% the 1st time and 78% the second time.

For me, it seems that the batches I mash high and long, tend to attenuate very well, but I would not say it has a direct correlation.

Fermentation also starts rather quickly, with T-58 starting 4 hours after pitching dry, with no rehydration.