Fermentation taking longer with Grainfather

[Harbey]

So usually my airlock has stopped bubbling by about day 4 and I leave it another week or so before bottling (usually on a Thursday or Friday evening so I can brew again on the Saturday). I did my first Grainfather brew on Boxing Day and now, 7 days later, the airlock is still bubbling away at a steady rate. Is this just a coincidence or does the Grainfather do some magic which slows down fermentation? I used to be BIAB with wildly variable efficiency.

The brew was a fairly ordinary IPA with an OG of 1.060, 22L in the FV and using MJs West Coast yeast at 19C. Was hoping to bottle this weekend so I could get another brew done but looks unlikely now.

 

[Bigcol49]

Hi!
Was your mash temperature lower than normal?

 

[Leon103]

Different yeasts?
I wouldn't really bottle after a week.

 

[Harbey]

Same yeast as usual - certainly one I've used several times before. Mash temp should have been the same but perhaps it's the GF's thermometer which is calibrated differently to my old one.

Not planning on bottling after a week btw, usually 11-12 days. Was hoping to do this Saturday evening or Sunday morning so I could brew Sunday but I think I better wait a week (I'm just a big kid wanting to play with his new toy!).

It's still bubbling

 

[peebee]

It wouldn't surprise me if the your previous (BIAB) mashing temperatures were actually a couple of degrees cooler than you thought. The GF is pretty good at keeping a consistent mash temperature as set, so would produce a less fermentable wort than you are used to.

I got a GF recently and I notice longer fermentation times. But that's due, I think, to the smaller batches; the GF only produces 23L (...ish) whereas the main brewery knocks out 40-70L. There always used to be the idea of "small batch" effect (which everyone used to blame for miscellaneous ailments - much like people blame "infection" these days) - perhaps it's what I'm experiencing and "small batch" has its boundary between 25 and 40L? Or perhaps I'm suffering "infections"?

 

[Harbey]

Still going.

 

[HarryFlatters]

I've got a dunkelweissen that I brewed on the 8th December only just now slowing down

I feel your pain...

 

[chewie]

Could also be slightly cooler ambient temps affecting your fermenter at this time of year, a couple of degrees can make a world of difference, or the fermenter being completely airtight when previously it hasn't been.