Fermentation restart query

[Lawrence R]

I’ve brewed a NEIPA for the third time now. On the first and this occasion, having added hops in secondary, fermentation seems to have restarted after a few days in secondary. The first time I racked off into secondary after the SG stabilised and used leaf hops, this time it’s in a brewtech chronical and I used pellet hops having drained the yeast and trub. The first time the SG did drop further and the temp control was reasonable. This time the chronical is in a converted fridge with temp control from an Inkbird.
Any idea why this should be happening?

 

[The Baron]

There are quite a few reasons why fermentation can start again
1. it has not restarted but as you have added hops it gives necleation points for CO2 to be released.
2. fermentation had not fully finished and when you added hops it stirs up the yeast slightly even if you are careful.
3. you may have moved the FV which again slightly rouses the yeast/trub and a difference in temp if put in a slightly warmer room.
The only surefire way to make sure fermentation has finished is to take multiple hydrometer readings as some brews seem to have finished but may take those extra couple pof days to drop the last point or 2 and adding hops/moving may just be enough to restart that last bit of fermentation.
I dry hop differently to you by doing it whilst the last bit of fermentation is going say after 4 or 5 days so that the first vigorous fermentation has finished. I then leave them in for the required days say 5 days then removed them and leave until the 14th day-ish then cold crash. This generally means that fermentation has had 14 days so fermentation has usually finished.
This is only my way as some people dry hop near the end but IMO this means that you will not have any problems with adding hops that may restart any fermentation again this is only my way and other brewers doing it with other variances. This is only 1 way and is not the only way so ypou will get other replies just read them all and do what suits you and your system best

 

[Lawrence R]

Thanks. That’s v helpful

 

[foxy]

I’ve brewed a NEIPA for the third time now. On the first and this occasion, having added hops in secondary, fermentation seems to have restarted after a few days in secondary. The first time I racked off into secondary after the SG stabilised and used leaf hops, this time it’s in a brewtech chronical and I used pellet hops having drained the yeast and trub. The first time the SG did drop further and the temp control was reasonable. This time the chronical is in a converted fridge with temp control from an Inkbird.
Any idea why this should be happening?

As Baron has pointed out there are reasons that you will get activity starting up again, another and I have posted this before. Think where sugar comes from, it comes from plants and hops are no exception there will be some sugar maybe not so much in the hops introduced so there is a good chance of a seeming restart to fermentation.