I have the Blichmann floor model and a 15gal kettle. As Mr. Barleycorn has suggested, bring it up
slow. What I do is watch that temp, when she crosses about 140f, down we go on the heat (and, cooling water to the condenser is enabled) to just blobs and I make the rise into the foreshots zone
slowly. We are after a balance in the column, right? So I try an build to that ever so slowly. I've done hard and fast until I see the first foreshot drips, but it's an unwieldy bitch to get under control from there - temps just wants to soar and it takes time for that kettle to settle and I ended up see-sawing temp adjustments and smearing.. Yuch.
My experience is it's easy to maintain once I get to temp, and I seldom have to
add heat. For my experience, I wait a good 3 mins between adjustments to see what effect I've made - I understand we cannot control via the temp on pot runs, but it is a guide - I just have to remember that the temp I am observing is
column temp and the kettle is
warmer. I have an infrared temp gun (Like the HVAC boys use) I use to get a reading off the kettle near the base, so I have some idea what temp is occuring in the kettle. Once I find the sweet spot, she'll stay stable until the temp goes up a tad thru the natural progression of the run. Even then, I try to be careful about making any changes on the heat. what I have observed is that the column temp will oscillate back and forth by 2-3 degree's but then settle back to the stable "current normal" - As a relative newcomer, I document column temps observed for each cut jar I'm taking along with distillate temp, abv, and cut jar # - for my records more than any thing else - but I do get trending datum after a few runs I can observe and analyze.
Now, I
have made the stupid mistake of moving the bottle (or bumping it) and getting an unwanted adjustment and upsetting the balance. Even them, I try hard to avoid making any large moves to regain temp. As so many here say,
low and slow..I love that Blichmann.
Also, careful with the diffuser plate, I think I have read where it can melt when using it over a burner under high settings. I don't use it as a diffuser when I use the Blichmann. It does serve exceptionally well as a table top platform for my catch bowl (filled with sand and the jars set in that.) under the condenser. I have not yet been sucessful at building a decent parrot
Now, about the cooling - I save back my 2.5 distilled water jugs and freeze tap water in them and I put one into a 50 gal trash can with about 10 gals or circulating water. I find I can get about 6-8 cut jars (read: half pints) done and I need a new block. I got thru about 4 blocks per run, but I can refreeze them so I am not burning thru bags of ice.