Mash length and attenuation

[Clibit]

I've been reading about longer mash times increasing attenuation during fermentation. Seems to make sense and may help explain my higher FGs in recent brews, which have had short 30-40 minute mashes.

Anybody understand this better, or have any info or evidence, or want to dispute it?

[Johnf]

This is going to be interesting, well hopefully it will.


Cheers
John

[Notlaw]

Hmm, interesting. Only mashed for 60 so far. May mash for 90 next time and see if anything changes.

[serum]

That's a pretty short mash. I'd say try a longer one and compare.

[Clibit]

That's a pretty short mash. I'd say try a longer one and compare.

I've generally done 60 minutes, sometimes 75 minutes. Recently did a 30 min with no loss of efficiency so done a few more, same efficiency, but higher FGs.

[BrannigansLove]

When I used to do BIAB, I used to do 90min mashes as standard. Sometimes it felt like some of the beers lacked body, so there might be something in this. I guess the longer mash time allows the enzymes to break down some of the more complicated sugars.

[Sadfield]

I think I it's akin to chopping down a tree. In an hour you might chop it into a few large logs, given a day you have the time to cut it down to kindling. Give enzymes longer time to split up long chains of sugars, the more simple(?) sugar, that the yeast is able to consumer, is available.

That's my understanding, anyhow.

I'm not sure whether the difference would be too noticeable between 60 and 90 minutes, as it would be between 30 and 60.

[Clibit]

Yeah you could be right. Maybe a short mash is a useful tool for low ABV beers, or any beer you want some residual malt.

http://www.experimentalbrew.com/content ... -mash-time

http://www.homebrewtalk.com/showthread.php?t=60576

"Well, the first thing I learned from my experiments was, if you mash for anything over like 20 minutes, efficiency isn't affected significantly at all."

"What I did notice is that with mashes of less than 30-35 minutes, the fermentation would sometimes quit early, with an attenuation of only mid-60s in a lot of cases. This did NOT happen with every batch, and it did not happen with every yeast strain."

"The next thing I found was that if I mashed for at least 40 minutes, then every batch turned out spot on perfect with respect to both efficiency and attenuation. So, I have been mashing for 40 minutes pretty much ever since, except for those cases where I got lazy or distracted or purposely wanted a bone dry saison or something like that. But for about 90% of recipes that specify 60-90 minute mashes, I mash for only 40 minutes, and I get results that I cannot distinguish from what was intended."

*******

"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."

"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."

[Mr. Dripping]

A short mash will promote a higher FG.
I brewed a low abv (2.5%) beer last year for a competition and used a 30 minute mash to keep the FG a tad higher than it would've been and keep a good body in the beer. I also mashed at 71.

Conversely, to try and save a bit of time on brew day, I used to mash overnight.....so 6-8 hours. These beers had a lower FG, sometimes by up to 4 points......as a result the beers tended to be on the thin side and I have stopped the overnight mashing.

[Clibit]

A short mash will promote a higher FG.
I brewed a low abv (2.5%) beer last year for a competition and used a 30 minute mash to keep the FG a tad higher than it would've been and keep a good body in the beer. I also mashed at 71.

Conversely, to try and save a bit of time on brew day, I used to mash overnight.....so 6-8 hours. These beers had a lower FG, sometimes by up to 4 points......as a result the beers tended to be on the thin side and I have stopped the overnight mashing.

Cheers Mr. D. This might help me get closer to target FGs. But with mash temp, mash time, yeast strain and health and grain bill to factor in, it's seeming more complicated than ever! I guess most brewers do the same thing every time and learn what to expect. I'm always trying things.

[serum]

I do 75 minute mashes and I tend to find my beers are on the dry side so I might actually try cutting it down to 60 mins at some point to see what happens.

I don't mash out and my boiler doubles as a HLT so it takes a while for the wort to go from draining to boiling which could also affect things.

Having said that despite attenuating low, my last few beers have been a lot maltier and sweeter but I'm doing other things to get those flavours. A shorter mash might solve it with less mucking around.

[Clibit]

Maybe try 45 mins? 15 mins possibly not enough to make a noticeable difference?

[serum]

I'll do it bit by bit, I'm probably messing with too many variables otherwise

[Chug]

I'll start with the conclusion and then you can read the rest ifn you can be arsed, but they're good articles.

QUOTE:
Conclusion

Attenuation and efficiency of the mash are effected by many mash parameters. Some have more impact others have less. When using a single infusion mash, temperature and time are the best parameters that a brewer can work with to target a specific fermentability of the wort. The time should be long enough to allow for complete conversion of the mash or at least a wort that doesn't contain any starch (negative starch test). This might be achieved after 15-30 min, but a longer mash rest may be needed to achieve the desired fermentability. The mash pH should always be controlled and kept between 5.4 and 5.7 when measured at room temperature (5.05 - 5.35 when measured at mash temperature). This pH control can be done through the brew water design (residual alkalinity) and/or acid/salt addition to the mash.

Brewers that don't mill their own grain will not be able to effect the tightness of the crush and will have to accept lower conversion efficiencies or ensure that the mash has enough time and "strength" to achieve an acceptable conversion of the starches. If the mill gap spacing can be controlled the conversion efficiency can be improved through a tighter crush. But at some point the crush might be to tight for a resonable run-off speed.

The thickness of the mash doesn't seem to effect the fermentability of the wort that is produced but thinner mashes can significantly improve the conversion efficiency. As a result brewers who see low efficiency from their mashing may try to use a thinner mash (3-4 l/kg or 1.5 - 2 qt/lb) as they were shown to convert more starches.

When working with large amounts of highly kilned malts attenuation and efficiency problems can arise due to the lower diastatic power (enzymatic strength) of these malts. This can be counteracted by lower mash temperature and longer mashes or the addition of a diastatic stronger malt to the grist (e.g. 10-20% of Pale/Pilsner malt)

While the water composition may also have an impact on attenuation and efficiency besides the change in mash pH through the residual alkalinity, its impact is considered small and secondary.
ENDQUOTE:

SOURCE:
http://www.braukaiser.com/wiki/index.ph ... edirect=no


http://www.braukaiser.com/wiki/index.ph ... Efficiency


and you must have seen this before comparing mash times on the same brew.
http://brulosophy.com/2014/09/01/does-m ... t-results/

[Clibit]

Excellent, thanks Chug.