Mashing & Boiling - longer vs shorter times

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RichHall

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Hey guys

Just wondered what the differences are in completing a long mash and boil - say 60 - 90 minutes each, versus doing a shorter version of each stage - such as 30 mins each?

What do the longer mash and boil add to the recipe/brew that a shorter mash and boil wouldn't?

Also - if I had a recipe that wanted a 90 min mash and a 90 min boil, but I wanted to follow 30 mins for each - what impact might that have on the overall recipe and outcome of the brew?

Cheers!
 

MmmBeer

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Very basically, a longer mash will extract more sugars from your grain and a longer boil will extract more bitterness from your hops. However it is law of diminishing returns, so that doubling the time will not extract double the amount.

Also a longer boil time can help reduce off-flavours, such as dimethyl sulphide, especially if using very pale malt.

If you really wanted to convert a recipe from 90 / 90 minutes to 30 / 30 minutes, put it through some brewing software at 90 / 90, note the OG, IBU's colour etc, then reduce to 30 / 30 and increase grain and hop quantities to achieve the same results.
 

HarryFlatters

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Also a longer boil time can help reduce off-flavours
I'm doing a brew tomorrow where all the reading I've done says to do a 90 minute boil to drive off some scary sounding chemicals, so that's what I'll do.
 

MmmBeer

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I'm doing a brew tomorrow where all the reading I've done says to do a 90 minute boil to drive off some scary sounding chemicals, so that's what I'll do.
I swapped to 90 minutes a while back, after a run of DMS affected brews. I have now put that down to a suspect sack of malt and have scaled back to 60-70 minute boils. I haven't been tempted to experiment with sub 60 minutes.
 

Rodcx500z

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Mmmbeer, I worked in a bakery for 30 years the trouble you get with ingredients is amazing, we had a rule, there are dick heads at work in all industry's and they don't care much for the consequences of their actions or how money is involved or how much head scratching it causes trying to find out were it went wrong.
 

the baron

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I do not do longer than 45 mins mash or boil and get full conversion with the usual efficiency seems not be affected. I can do a full brew in around 4 hours including a 10 minute mash out and cleaning up. I rarely do bittering hops nowadays and use late additions to get more flavour and my bittering from these additions
 

MrRook

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When I was still doing all-grain I switched to 45 minutes mash and boils and noticed no difference in the final results.
 

Honk

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I've also reduced my boils to 45ish minutes (sometimes 30) and not noticed a difference. Still mash around 60 minutes though plus however long it takes to get to mash out temp.
 

matt76

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Hey @MyQul , weren't you saying something a couple of weeks back about this? I think it was something about how mash time affected body/mouthfeel???
 

MyQul

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Hey @MyQul , weren't you saying something a couple of weeks back about this? I think it was something about how mash time affected body/mouthfeel???
Probably. When I make my low gravity bitter/mild, I mash for only 40 mins at 70C. As MmmBeer has mentioned, this seems to increase the body so the beer isnt watery for such a low gravity beer (usually 1.036 OG)
 

Honk

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Interesting what @MmmBeer said above about a particular batch of grain needing a longer boil to avoid DMS. Seems like there are a few of us doing shorter boils and getting away with it but maybe one day we will get caught out?
I will need to check but I'm sure in Ron Pattisons book "War" it mentions brewery's reducing boil times to save energy during both first and second world wars but I don't think they went below 60 minutes. Maybe modern malt is more reliable but I still think commercial brewers don't reduce boil times as much as we are (unless anyone knows different?)
 

Ghillie

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Haven’t found any difference between 60 and 90 minute single infusion mashes. I’ve done the incremental iodine testing and everything is more than complete at the 40 minute mark.

Step mashing however does extract more sugars from the grains, however this is very much more down to the temperature steps involved vs the total time.
 
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