Finished or stuck fermentation?

[Christomac]

Hello - I've made a NEIPA with a starting gravity of 15.5 brix (8.4%). I made a yeast starter using 1-yr old liquid yeast (London Fog). After little activity during the first 2 days at about 65º, I put a warming belt on the bucket which kick-started the fermentation. After 3-4 days, the fermentation was down to about 8 brix. I transferred to a carboy with the warming belt and days later it is down to about 7.7
Should I consider this fermentation done?
thanks

 

[VikeMan]

Are you measuring with a refractometer or a Brix hydrometer?

If refractometer (which requires correction using a beer refractometer calculator, and not just a simple brix to specific gravity calculator), your Final Gravity is probably about 1.012 (Novotny's formula) or 1.013 (Terrill's formula). So, likely finished or very close to it. Wait 2-3 days and measure again to be sure.

If you're using a brix hydrometer, your Gravity is at about 1.031. So, clearly not finished.

 

[Christomac]

Thank you - that's very helpful. Yes, I was using a refractometer and didn't know about the correction formula.

 

[dmtaylor]

Novotny:

https://www.brewersfriend.com/refractometer-calculator/

Terrill:

http://seanterrill.com/2012/01/06/refractometer-calculator/

 

[hotbeer]

It's done fermenting when the SG, Plato, or brix stops changing. So you won't know that until you compare to another. Though typically 2-3 days apart is suggested, I've had on several occasions a 1 point drop in SG over the course four days. Once for two consecutive times with the same brew.

We call our vessels fermenters, but that seems to have some thinking that it's time to move on when the beer finishes fermenting. I don't agree with that. Leaving beer in them for 10 days more or even several weeks longer lets yeast have time to do other things besides the fermenting. They do clean up some off flavors afterwards. And longer times means more stuff in suspension has time to settle to the bottom of the FV instead of the bottom of your bottles or keg. But possibly it's not as big an issue for kegs drawn from the top.