Anyone still using sanke kegs for brew vessels?

I have a three tier setup with all sankes as my vessels. I built it trying to save some money but have run into a few problems. I built it out a few years back and since then didn’t brew a lot. I did not use it a lot due to a lot of clutter in the garage and not wanting to drag it out. Recently I put up a shed to alleviate the clutter, and have ramped up my brewing. I am just now getting to dial in this set up.

As I said all three vessels are converted sankes. It’s done great with the weather above 65 degrees. Last Sunday we had cooler weather and lots of wind. It was also one of the smallest grain bills I’ve done lately. I missed mash temp by 20 degrees and ended up having to direct fire the mash with stirring to raise to 150 or so. I hope to avoid this in the future. I know that a lot of it was the small grainbill. Though I’m capable of doing 10gallon batches Ive been doing 5s as I don’t need 10 gallons of every thing I make.

I’ve also had gravities about 10 to 20 points higher than estimated. I know thats due to increased boil off rates. The mash tun has a false bottom and is wrapped in about an 1 1/4" think blanket of reflectix. That treated me well on my previous system. I also use a lid to to help hold on to temp.

Just wondering what other out door brewers do to account for temp and humidity changes? I know that some loss is due to the size of the mash tun and temp absorption. I’m also considering building a wooden base for the mash tun to set on to be a better insulator than the empty space below it.

Missing your mash temp by 20deg sounds more like you messed up your strike temp. How did you calculate that. As far as evaporation rate I check my boil volume at 15 and 30 min intervals and open or throttle my burner to compensate. If you need more insulation put it on top and sides. Sure there is some heat sink but temp mostly rises plus with insulation on the bottom you couldn’t fire your burner.

I have the same set-up, but brew in my garage. The MT is the weak spot.

I heat my HLT up to 190 and add a bit of water if needed to raise the temp. Sometimes heating and recirculating.
Generally only needed in the winter.

I don’t use a converted keg but I do use a 15gal pot so essentially the same thing. I direct fire it for my target temp, add the grain, wait a couple mins, then place a couple heavy blankets over the pots. Usually only drops a degree or two over an hour. If I have a large headspace then I will go out and reheat after about 1/2 hour.