Blowtie + fermzilla

[chazam]

How does this setup work?
So I 1) BIAB to make my wort, 2) cool it down, 3) siphon to fermzilla, 4) add the yeast, 5) close the lid and 6) add the air lock. Alright. But I have the equipment for beer fermentation under pressure but now much idea on how to do it. I'll try it in the next batch. I have a blowtie and CO2 tank. Should I after 5) add 5-15psi from CO2 tank to other fermzilla ball lock and attach the blowtie to another? And is the blowties purpose to see the pressure level, let out pressure if one wants to dry hop or drop the pressure for whatever reason? Do I have to daily monitor the pressure levels and let out pressure if it gets too high? Does the pressure level flunctuate?

 

[GoodTruble]

The bow tie will hold a set pressure up to 15 psi. You can also tighten or loosen it to increase or decrease pressure. But it should just hold whatever psi you set and then release the excess CO2 as needed to maintain that psi.

You shouldn't need to add CO2 (until it's time to transfer) because fementation will create way more CO2 than you need to spund or carb. I usually use the regular airlock for the first 2-3 days, then screw on the bow tie, left mostly open and then tighten a bit more until I hit the desire psi. You could also just start with bow tie left open, I'm just paranoid I will forget to loosen it enough and over-pressure the fermzilla overnight during the early, most active fermentation.

 

[micraftbeer]

I collected some information on pressure fermentation and it is on a resource post on homebrewfinds (link below). But here are some highlights I'd say based on your questions:

1. Fermenting under pressure isn't automatically a good thing for your beer. Like almost all things in brewing, you should go into it with a purpose, and have a specific thing you're going for.
2. As @GoodTruble noted, you don't need to add bottled CO2. And based on feedback I gathered, there is belief that letting it ferment without any pressure for the first 24 hours is a good thing for your yeast.
3. The beers I've brewed where I split the batch and half was under pressure at warmer (60-65F) temperatures, and the other half without pressure and fermented cold (50-55F) do not come out identical. So again, make sure you're doing it with purpose, not just because your fermentor is capable.
4. One area that is pretty much universally beneficial is dialing up your spunding pressure at the tail end of fermentation. When you're within a couple points of gravity of expected FG, if you close down the valve slightly and let the fermentation end up with 2-5 psi of pressure, that's a good way to help keep your fermented beer free from oxygen or other unwanted stuff coming into your beer.

https://www.homebrewfinds.com/2021/08/fermenting-under-pressure.html