Finally managed to get a decent brew day on the books. Irish red for St. Patricks day, turned out 10 points lower than expected but I really don’t mind that. (1.032 OG, boil off was way low. Was supposed to be 1.042.)
What I do mind is my mash tun. I’ve been having issues with lower than expected mash temps, and upped the ante on how I measure temps for this brew…and I lost a whopping 16 degrees. Weather was upper 40’s, no wind.
The cooler was about half full. I bought this size cooler with the intent of brewing 10 gallon batches for lower gravity beers, and 5 gallon batches for higher gravity beers. Currently the water supply for my counterflow chiller is not available, so I’ve been brewing 5 gallon batches so the brew kettle can be carried into the kitchen. There I can use my immersion chiller hooked up to the kitchen faucet.
So did I lose all my heat because the cooler wasn’t full enough? I’m honestly not sure that’s all it is…temps fell from 156 to 140 in about 50 minutes.
Shouldn’t drop that much. Do you pre heat? Have you measured 10 minutes in to see where it’s at? I have brewed in <32° temps and lost only a couple degrees.
ETA - if you don’t pre-heat, do you account for the temp loss caused by the cooker being cold?
FWIW, I cover my cooler with a blanket or sleeping bag, and the put a dumbell weight on the lid. I’m still puzzled at such a high temp loss though, even if the lid doesn’t seal perfectly.
I’m wondering now if wort has made it into the insulation and has caused it to deteriorate. The cooler is setup similar to how Denny’s does his, just with a different sort of bulkhead through the cooler.
If the insulation is deteriorating it’d explain why this issues seems to be getting progressively worse.
Talked to several homebrewers at work, they’re equally stumped. Has to be something with the insulation, these rates almost suggest mashing without a lid.
I’m kinda pissed, was hoping to limp this mash tun along till we could move out of the condo and into a house.
This brewday was also a try to see how my system help up to a low oxygen mash…and it failed miserably. So I’m already considering moving on from this cooler.
Pre heat your cooler, I bet that’s the problem. Add water 10-20 degrees hotter than you strike temp shut the lid and wait a few minutes. Open the lid and recheck temp. The cooler will absorb a decent amount of heat right off the bat, which is likely most of the loss in temp you are seeing.
But why the change in that shift? Brewing is all about repeatability, and this tun has been anything but. The cooler is always stored inside, at about the same temp (plus or minus 2oish).
And I hit my starting temp, after a few minutes (once all dough balls were broken up/everything was mixed in)the temps in the cooler were between 154-156o, depending on where I took the reading. If I wasn’t using water that was hot enough to bring the cooler and everything else up to temp I’d never had hit my temp to begin with.
Dough-in took longer than normal on this beer, I was glad I purposefully overshot my strike temp.
gotta disagree. He’s losing temp over the ocurse of the mash, not the initial dough in. I’d echo everyone elses sentiment and say the insulation is shot. you can get a new cooler cheap at wal mart, or I see them all the time at garage sales.
Crazy thought…drill a small hole into the insulation near the bottom and see if anything leaks out. You might need to drill one near the top too.
Also check if the insulation that comes out with the drill is damp.
Phil M - what kind of cooler, out of curiosity? I’m having a hard time picturing the wort leaking into the interior and ruining its insulating properties. But that may very well be the case and a new cooler gets you rolling again. But with all the cooler mashers here, I’d just think we’d hear more stories like this if that were the case ( first time I’ve heard of it). I know Denny is still on his original cooler, still sealed with the mini keg bung IIRC. Not trying to be argumentative, just puzzled.
The hole for this fitting isn’t jacketed in any way, so if you take it out you have ready access to the insulation. Wondering if something got behind the bulkhead. Perhaps those cheap rubber seals couldn’t handle the heat.
I’ll take the whole thing apart when I can, but doing so will completely undo how I’ve got the stainless mesh/drain tube attached. This setup was version two after a bad leak from version 1. I’ve got the funds to “upgrade” to the 10-gal SS brewtech mash tun, I might just go ahead and do that. The big square cooler can’t be drained into my tiny kitchen sink without taking the lid off. The SS mashtun is round, and I wouldn’t have this issue. (I can clean my 15 gal kettle on it’s side and drain it into the sink without issue.) Still would be a splurge though.
Well I ordered the new mash tun. I’ve got another brew day planned this coming weekend, and it kinda has to succeed or there will be no stout at our annual St. Patrick’s Day party. Better to perhaps spend too much and be sure of getting a reliable mash I feel, and as I’ve mentioned this has been something I’ve been considering.
Still going to get to the bottom of this. If the cooler can be salvaged I’ll give it to a friend who’s trying to make the jump from extract to all grain.