Temperature fluctuations « Brew UK Forum

Temperature fluctuations

11 months ago | HopLover (Member)

Hello,

I am trying out my new STC 1000 on my 2nd hand fridge for the first time. I stuck the sensor to the outside of the FV with some tissue paper tapped over it. It was fine at about 19-21 degrees. This evening, after 3 days at this temperature, I tapped a thick sock over it with more tape (after reading around) and had a slight freakout as I watched the temp rise to 22.8 or something! Now the fridge has kicked in to bring the more "true" temperature down to 20 degrees. School-boy error!

I am bit worried about the temp fluctuating and dropping by 2 degrees pretty much instantly. Do you think I should raise the temperature to 22.5 or so? I guess whats done is done, because by the time I get any answers it'll have been at the lower temp for a night.

If you have a higher temp for the initial phase, and slightly lower for the secondary stage, I suppose less stuff like Diacetyl will be cleaned up. I like fruity beers, but have already had a few with slight off flavours that lessen with proper chilling, but its not ideal. I am heading for another?

I need to look after those yeasties more, poor things.

P.s. I'm using US-05

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Responses

Hamish:

Posted 11 months ago by Moderator

What is the temperature difference set at?. I have no experience of the STC 1000 but if its anything like the ATC800+ set it to + or - 1°C, don't change the temperature setting. Imagine what the temperature fluctuations are like in your house, you brewed perfectly good beer didn't you?. US-05 is a tolerant yeast it'll be fine.

Planning: Wheat beer fermented with Schneider Weisse yeast, a Stout, lots of hoppy pale ales
Fermenting: Summer pale ale
Maturing/Conditioning: Marynka pseudo-lager
Drinking: Wheat beer, ESB, Vienna lager & shop bought stuff

saracen:

Posted 11 months ago by Moderator

If you place the sensor on the outside of the FV you need to insulate it away from the outside temperature. With mine, I cut a square of 1 inch thick polyfoam that arrived acting as packaging for something or other, made a recess on one side the probe would fit into, stuck some adhesive silver tape in the recess and stuck the contraption on the side of the FV. Works great, but plenty of others report a few layers of bubble wrap do the job. Personally, I'd want to insulate it better than that for use in a fridge.

The general rule with temperature which we all seem to use is, start the fermentation at the low end of the yeast's temperature range and raise the temperature at the end of the ferment to help the yeats clean up. For most yeasts that mean start at 18°c for a week of so, then raise to 21° or 22°c for 3 or 4 days.

If you're not living on the edge..... you're taking up too much space!!

Planning: - To get some more brews on now the weather's a bit cooler
Fermenting: - Ginger Beer experiment
Conditioning: - A normal bitter with Styrians
Drinking: - All of it!!

E-mail: arnyfris@gmail.com

Hamish:

Posted 11 months ago by Moderator

Hmm, my sensor is just stuck to the inside of the fridge. Attaching it to the fermenter and insulating it seems like a lot of fannying around to me, do you need to be that pedantic?. :wink:

saracen:

Posted 11 months ago by Moderator

Thinking about it, with the FV in a sealed environment like a fridge, probably not, provided the temp of the wort matches the temp of the fridge. On the other hand, if you put it in the fridge at a higher temp and want to lower it, the sensor will never know the temp of the wort.

Hamish:

Posted 11 months ago by Moderator

Why does the sensor need to know the temperature of the wort?. The whole purpose of the brew fridge is to control the fermentation temperature, over a few hours the fridge and wort will equal out.

Maybe I've got some sort of mental block on this one and I'm missing something obvious.

saracen:

Posted 11 months ago by Moderator

I think you're right, Hamish. Not thinking laterally today.

Nath:

Posted 11 months ago by Moderator

I wouldnt worry mate. The reading of 22.8 may have happened due to the fact the sock you placed on the sensor was a lot higher temp than the fridge so it would read higher for a while. In the "yeast" book its been said that most yeasts produce most flavour compounds in the first 3-4 days and they go about munching the last sugars and "mopping" up afterthemselves after that period so I wouldnt worry at all. A small rise in temp for a short period aint gonna do no harm.

Hamish - in the brew fridge the temp controller is controlling the ambient temp so it dosnt really matter where it is, but if you do insulate it to the fv then it will give a better reading of whats going on in the wort itself which in the grand scheme of things would probably give you more control - but on our small scale I woulnt think any way would be better. I do know that some people put the probe in a glass of water to give a better estimate on whats happening but I wouldnt bother as I dont think it would help being that the yeast in the wort produce temperature anyway.

When I brewed in a garage I stuck the probe to the fv and used a heatmat to control the heat - I never used the cooling circuit to cool as the garage temp was always cool enough.

Drinkin' - nowt, it's all gone

Plannin'-
Loads a beer after an upgrade!

nathbrew@gmail.com

Hamish:

Posted 11 months ago by Moderator

Each to their own I guess, we're not talking about huge differences though are we?, way too pedantic for me.

saracen:

Posted 11 months ago by Moderator

Years ago, I met a Fire Eater who lived on an old bus. I actually mended his bus on a dark, cold night and he invited me in for a drink. "Cider", he said. "Make it myself!"
He dragged a soiled towel off a bin in which was something looking like the surface of a cess pit with fag ends, paper, flowers and all sorts floating on it. He dipped the glass in and offered it to me.
He wasn't quite pedantic enough for me.

Nath:

Posted 11 months ago by Moderator

lol, classic!

Drinkin' - nowt, it's all gone

Plannin'-
Loads a beer after an upgrade!

nathbrew@gmail.com

Hamish:

Posted 11 months ago by Moderator

:lol: You should write a book saracen.

saracen:

Posted 11 months ago by Moderator

You should write a book saracen.

I did. Took it to a publisher and they loved it. Said it was a great story, well written, but they didn't want it. Why? No sex and violence in it...... And before you ask, no, it wasn't my autobiography!!

Mark:

Posted 11 months ago by Member

Just to let you all know i am absorbing all this debate on where the probe shall go and what it is encased in, as a neutral whom is considering this for myself i think Saracens sounds the most logical encasing the probe in polyfoam or polystyrene. The bubblewrap sounds a good solution to but i would hazard a best guess that Saracens method accurately measures the FB best due to its better insulation. Yes maybe Phaffing around but if you pay attention to small detail then rest takes care of itself.

Planning-Connoiseur Johannisberg Riesling
Fermenting-Nowt
Conditioning-Proper Job Comp Beer,Kenridge White Merlot
Drinking-Raspberry/Lime cider,Grenache Blush Rose,Coopers modified lager
SG Chardonnay Wine

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