Another temperature control thread (Experiment check)

[GotDrunkThenLost]

So I'm starting down the dark path of trying to have proper control of fermentation temps. I don't have room for another fridge/freezer in my apartment so my current method involves:

A big bucket sat in my spare bath with fermenter inside that and water up to the level of the beer.

Another bucket in the bath filled with water and 3*1 gallon(ish) bottles of ice I switch out every morning and evening.

I've got an STC1000 that controls a couple of small aquarium pumps (one doubles up for use in my wort chiller) that switches water between the buckets to chill the water around the fermenter.

I'm still unsure of how accurately I'm controlling the beer temp though, between the lag time of temperature change of the water affecting the beer and the heat given off by the fermentation process. If I use the beer temp to control the STC but then affect the water temp in the bucket I suspect I'll get much greater swings in temperature. I'll be dumping a lot more cold water in to the main bucket while the beer slowly drops but it would probably continue dropping afterwards.

So I was considering buying a couple of these and measuring temps of the beer and water over the next several brews. I've been rotating my fermenter between glass and plastic and will probably continue to do so.

Would it be worthwhile to do the following experiments? To see if I can work out a sweet spot for both the location of the STC sensor and the temperature to set the STC to aim for:
These would all be 5 gallon batches and if I can get the temp probes to register the temp every 15-30 minutes over the course of initial fermentation
1) Glass fermenter - STC probe in the water, STC set to a couple of Celsius below the bottom end of the optimum fermentation temp.
2) As 1 but with plastic fermenter.
3) Glass fermenter - STC probe in the fermowell, STC set to the bottom end of the fermentation temp.
4) as 3 but with plastic fermenter

Then repeat for the 3 kinds of yeast I use for my favourite brews (WLP002, WLP007 and WYeast 1056).

My day job is as a statistical programmer so I can easily convert the resulting data into a time series graph (if I can't I need sacking and shipping back to the UK) to overlay the results of the water and beer temp readouts over each other. Hopefully with that I can get a better understanding of what is going on.

What are your thoughts? Is this worthwhile to try to get to the holy grail of good temps? Or am I just better off using methods 1 and 2 as my standard and going and getting brew out of the fridge?

 

[smizak]

I use a Son of Fermentation chiller so my chilling medium is air, but otherwise I find that wrapping the STC-1000 probe in foil and taping it to the glass carboy gives me dead on temps. The effect of the probe responding to the outside air temp as well as the fermenter helps modulate the cycling of the heat/cool mechanism. I've found that the internal temp of the carboy overshoots too much on my system if the probe is isolated to only the beer temperature, i.e. the air around the carboy gets so hot or cold by the time the beer hits a setpoint that it continues to rise/fall and the controller endlessly cycles. I would try and secure it to the outside of the fermenter wall.