Quick Temperature Changes + 15 years = failing fermenters. What to do?

[Woolsocks]

We lack a hot liquor tun in our pub brewery and lack the space to add one. Therefore, we heat sparge water in our kettle, pump the hot sparge liquor into a fermenter, the lauter, etc. as normal. We've always tried to cool the fermenter down ASAP (using the cooling jackets) so we're not putting chilled wort (not to mention yeast) into a hot fermenter.

After doing this for 15 years, we've had two tank failures (40% of our tanks) in the last month. First we "tin canned" a tank as we started cooling (thankfully it's still usable). Then, we had glycol leaking into our beer through a small crack in the inner shell of another tank. Upon further inspection, the inner shell is pulling away from the glycol jacket in several places, making the previously invisible dimples in the jacket start to stand out. It's been welded but of course I'll always be paranoid about that tank.

I always thought you could beat the heck out of anything made of stainless, but now we're thinking that the rapid change from hot to cold temps is weakening the tanks over time.

We're going to start letting the tanks cool more slowly, by just opening up the manway, etc.

Any other things we can do to prevent/reverse this sort of damage?

[froptus]

We have the same setup that you have. I don't like cooling with glycol because it dumps hot glycol into your reservoir. We use cold water to cool them down either thru the cip arm and sprayball or with a hose in our open fermenters.

[CopperKettle]

We do exactly as you describe except for using the cooling jackets.

A hot fermenter will not hurt your wort, the thermal mass of the wort is also MUCH higher than the stainless so it won't change the temperature more than a degree or two. What you are getting is a thermal expansion/contraction issue with high temperature gradients over very short distances. Let the tank cool down naturally as much as is wants on it's own after taking out the hot water but don't run the jackets at all until it is full of wort.

Pitch yeast after the cone is full but not (obviously) over the manway, or pitch yeast through a top port after filling is done, or use a keg to push yeast in the cone after filling with wort.

[PismoBrew]

You should consider using a tankless water heater for your strike and sparge water. This will eliminate the headache of the hot liquor tank. They have gotten very affordable and do a great job. Most of them come with a digital thermostat to set and adjust your temperature. I use the brand Norwitz and can get 4 gal. a minute at 180 degrees. I brew 7bbl batches consistanly with it. Very easy to install and use. If you would like any information I would be more than happy to answer any questions.
Tim Moscardi
Pismo Brewing Company
805-698-2765