Big batch temperature control

[Frodv]

Hi, I'm new to this forum and also a rookie brewer.

I am attempting a "speed-lager" and I am a little concerned about the temperature control during the ramping up and down.
I'm brewing a batch of about 50 gallons. What is the recommended placement of the temperature probe? Tape it to the side of the fermenter or just measure the ambient temperature?

And how long will it take to in-/decrease the temperature of the beer?

 

[ChelisHubby]

Gee Frody 50 gallons is a large batch to learn on. ON that size of batch I would think inside the beer would be best. But if the choices are between the out side of the fermenter and ambient then the out side off the fermentor wins hands down. Ambeint will make you bad beer until you know how yeast works and how much heat they create. I would defffintaly ferment on the cold side 3 degrees. How are you controlling the beers tempature? Forgive my spelling and possibly poor advice as I have had 5 pints. 50 gallons is large enough to bring different problems than what most here deal with.

 

[Frodv]

So maybe I should just cool the wort to about 48 F and pitch the yeast, leave at 48 F ambient temp, and bump the ambient temp up to 55 F after a week, and then after another week bump it up to 65 for a diacetyl rest for 3-4 days before cold crashing.
Maybe speed lagering is not such a good idea with a batch this size.

 

[Grod1]

please share how you will be making 50 gallons of beer.

 

[Frodv]

I use old water heaters all the way. As mash tun, hlt, boil kettle, fermenters and for lagering... All electric. 14 Kw total... HERMS.