Anything wrong with mashing for 2 1/2 hours?

[Beerbeque]

I'm trying to work a batch into a busy day and I need to be gone for 2 1/2 hours during the day. I am thinking about doughing in just before I leave to save time and then lautering when I return home. Is there any reason you know of that a 2 1/2 hours or so mash might be detrimental to my beer?

 

[gestyr]

As long as your temp maintains, you will be fine. I do this all the time, start the mash and then take SWMBO out somewhere and return in a few hours to sparge.

 

[lamarguy]

Assuming the same constant temperature, the wort from a 2.5hr mash will be more fermentable than a 1hr mash...I recommend you dough-in ~2F higher to compensate for the increased fermentability, expect a lower FG, or use a lower attenuating yeast.

 

[erock2112]

Assuming the same constant temperature, the wort from a 2.5hr mash will be more fermentable than a 1hr mash

I keep hearing this, but I'm not sure I'm entirely convinced... What's the science behind that? It seems to me that as time passes, more and more starches are converted up to a certain point, but once converted they would remain as-is, right? I'm no chemist - do the longer-chain, unfermentable sugars begin to break down into simpler sugars with exposure to the enzymes?

 

[lamarguy]

I keep hearing this, but I'm not sure I'm entirely convinced... What's the science behind that?

Mash Time Dependency of Wort Fermentability

Mashing for an additional 2 hrs after conversion is complete increased the apparent attenuation by 4 %. For 12 *P (1.048 OG) wort this means a final extract difference of about 0.5 *P (0.002 SG difference).

 

[suprchunk]

4% doesn't seem like much of a difference to adjust anything in the mash to compensate for. The only thing I see happening is the temp dropping and increasing it more, which should be compensated for. That is if you don't want a higher apparent attenuation.

 

[erock2112]

Mash Time Dependency of Wort Fermentability

Alright. Wasn't aware that the alpha-amylase would break down the sugars as well. 4% isn't a huge deal though.

 

[Wellshooter]

Hmm, I've been doing it since I started AG this year. Mash in the morning, eat lunch, take a nap, drain & sparge in the afternoon. Last batch was in the MLT for 3 1/2 hours. I'm not a brew scientist, just a home brewer, and it works for me.