Timeframe for temperature control when fermenting?

“Since it's typically the first few days that the yeast are most active, am I right in thinking that I'd only really need to keep it to temp during this time?” The first 3-4 days are indeed the most critical. During the Exponential Growth Phase is when flavors (and off-flavors) are developed.

“When can I stop worrying about keeping things cool, or shocking the yeast by letting it return to ambient temperature?” Once the Exponential Growth Phase is completed the fermentation goes into the Stationary Phase of Yeast Growth. Temperature control at this point is less critical in comparison to the Exponential Growth Phase. I personally become less concerned about the temperature of the beer in the primary once all signs of fermentation are complete.

You can learn more about the various phases here: https://byo.com/article/fermentation-time-line/

Cheers!

 

Nice article link, @JackHorzempa.

Can’t say I ever associated airlock aromas with olives before.

 

I also have less than desirable ferm temp control and did similar on my most recent brew.
My fermentor bucket went in a plastic tub with a few inches of water in it. I draped a damp bath towel over the fermentor and made sure the bottom of the towel was always in the water to create some wicking action, then directed the fan at it. It's not optimal but better than nothing.
Bottles of frozen water in the tub can help....put'em in, take 'em out as needed and stir the water occasionally.

....and yes, good info linked by @JackHorzempa

 

It is unlikely you will shock the yeast with a swamp cooler. We typically associate that with putting ambient temp yeast slurry into a cold wort. But the yeast should tolerate a fair amount of temp swing from cold to warm.

As always, use your hydrometer. When fermentation stops you are ok. But a few more days at colder temps will help to clear the beer.
Cheers

 

I doubt a swamp cooler is going to work that well in a high humidity environment...make sure you use ice bottles and change out frequently the first 2 days...after that not so much as a gradual rise towards 70*F is actually desirable for most yeast strains. Get a $3 fermometer and stick it on your fermenter and check often.

 

When you find a chest freezer to your liking be sure to get a temperature controller. I use the Johnson a419. Fairly simple and effective.

 

Inkbird is cheaper and easier

 

This is what I use with my chest freezer and I highly recommend it. I just attach the probe to the side of my fermenter and run the cord into the freezer through the lid. I have never experienced issues with temperature fluctuations using this method.

Cheers

 

I use this model on a chest freezer. The directions on the package are whack but there are plenty of useful instructions online.

 

The same model Inkbird is available HERE for 30% less.

 

@Lexicon just run the probe thru the door/lid and let the gasket close on it. No special drilling, etc. is needed.

 

As long as the door shuts tight enough and the stripping is good you won’t have any problems. At least in my case, my keezer holds its temp just fine.

 

Welcome. Fermentation temps are what made my biggest improvement to beer. Making clean beer and the ability to cold crash has been awesome.

 

A little known advantage of the chest freezer/keezer build is that cold air sinks and stays put.
Those open air ice cream freezers at your grocery store prove the point. Everything is reliably sub freezing beneath the magic line.

Front door refrigerators and freezers lose all of the cold air when they are opened, it falls out. Not so with a chest freezer. Cold air just sits in there.
Cheers.