Cold weather AG

Question for the masses:
It's currently 39 degrees here in Omaha and I'm attempting an AG porter. My cooler seems to be failing at maintaining a temp. I hit 152 dead on, then 5 mins later it dropped to 149. So I heated up a half gallon to about 190 and dumped it in, right back to 152. Now it's been about 25 minutes and I'm down to 147. Do I keep adding hot water? What's the recommendation?
Thanks for any help.

Start recirculating to maintain the temperature. This is best done with a HERMS/RIMS system and a pump, but you can do it manually. Drain a bit of your wort out of the mash, heat it, and distribute it back over the top of the mash. When doing this, avoid heating the drained wort above 160, as you don't want to damage the enzymes that are working for you. It'll be a fairly constant process since your temps are dropping so quickly.

You may be able to pull a decoction to get the same effect, but I have no experience decocting. I haven't heard of pulling a decoction to maintain temps, only to raise them. Maybe a more experienced AG-er could shed some light on that...

If it were me, I would have brought my mash inside where the ambient tempertures were higher and where your temperture loss would have been lower.

I know this advise is too late for today but it might help for the next time.
Also you could have insulated the mash tun with a blanket, including the cover.

Well, the brew session has completed. I think next time I brew I will take boo boo's advice and bring the mash tun inside. It's just a pain to transport everything...especially with 5 gallons of liquid inside.
I only missed my OG by 2 points so I think I'm allright. Thanks for the responses.

boo boo said:

If it were me, I would have brought my mash inside where the ambient tempertures were higher and where your temperture loss would have been lower.

I know this advise is too late for today but it might help for the next time.
Also you could have insulated the mash tun with a blanket, including the cover.

Click to expand...

That's not necessary. I brew in a lot colder than that with no problems. If you'd rather not lug your tun around (they can get a bit heavy when full) throw an old blanket around it for extra insulation when the air temp drops.

UNOmar, i just brewed my first AG last night in lincoln, same temps, I was using a keggle for my mash tun and just wrapped an old blanket around it and it held the temp right on (152) for 45 min.

Old blankets are the way to go.

Just another suggestion for the next batch... As already mentioned, the old blanket will help, but also, why not overshoot your strike water by 10 or 15 degrees (BEFORE PUTTING IN THE GRAIN) and let it sit in the cooler to warm it up a bit. You should get the bulk of your temp. drop in the beginning then it will (theoretically) calm down a bit after the cooler is good and warmed up. If you overshoot too much, you can just leave the cooler open a little longer and stir the water a bit to bring the strike water down to your calculated temp before adding the grain.

Reverend JC said:

UNOmar, i just brewed my first AG last night in lincoln, same temps, I was using a keggle for my mash tun and just wrapped an old blanket around it and it held the temp right on (152) for 45 min.

Old blankets are the way to go.

Click to expand...

Well I'll have to try that next time. How did your first AG brew session go?

It was great!

I missed the OG by .04

Most of that i attribute to the fact that i miscalculated the amount of sparge water needed, and i used 174 degree water, I am thinking had i used water that was 190 ish it would have brought the grain bed closer to 170 and thus getting me better efficiency.

But with an OG of 1.051 it should still have a good ABV when done.


P.S. Anyone reading this that has not built themselves a Counter Flow Chiller needs to put the keyboard down, take 80 bucks, and build it. That was the single most impressive tool of the night. 5 gallons of boiling brew down to 60 in 5 min. that deserves this

Glad to hear all went well.

I'm still using my immersion chiller which this time of year works quite well. 212 down to 80 in 10 mins. I don't have a spigot on my brew pot yet so I'll be using it for a little while longer...