FG too low

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Aug 10, 2020
Messages
4,683
Reaction score
471
Location
Quadring
I’ve just brewed a slightly tweaked clone of Harrison’s Vacant Gesture. This is a regular of mine and it usually turns out fine. I have been struggling with mash efficiency and fermenter volumes with my Brewzilla so I decided to change the default equipment profile in Brewfather and use the one suggested by Gash on the Homebrew Network. Brew day went fine expected OG of 1.038 and I hit 1.040
23L of wort in the fermenter again an improvement on previous brews. Cooled to 18°c and pitched 11g pkt. US-05 yeast fermented @20°c .Fermentation was very vigorous and after 5 days SG was 1.010 so I dry hopped with 31g of Mosaic. Then the fermentation went berserk 3 days later it had dropped to 1.005 and I dry hopped again with another 31g of mosaic. It’s now 13 days in and seems to have finished at 1.004 ! There are no off flavours or funky aromas the beer tastes a little bit thinner and harsher than usual but apart from that it seems OK not one to rave about though.
This has resulted in a beer with an ABV of 4.7% with an apparent attenuation of 90%
My predicted numbers were :-
OG 1.038
FG 1.007
4.1% ABV
Anyone shed any light on why my FG is low?
I am confident in my hydrometer readings.
Sorry it’s so long winded but I thought I would supply as much info as possible
 
I don't know, but I've never had a beer go anywhere near that low in 250 brews, many using that yeast. I'm tempted to say re-check it but you say you're confident in the readings, have you put the hydrometer in water to see if it's calibrated to 1.000?
 
I’ve just brewed a slightly tweaked clone of Harrison’s Vacant Gesture. This is a regular of mine and it usually turns out fine. I have been struggling with mash efficiency and fermenter volumes with my Brewzilla so I decided to change the default equipment profile in Brewfather and use the one suggested by Gash on the Homebrew Network. Brew day went fine expected OG of 1.038 and I hit 1.040
23L of wort in the fermenter again an improvement on previous brews. Cooled to 18°c and pitched 11g pkt. US-05 yeast fermented @20°c .Fermentation was very vigorous and after 5 days SG was 1.010 so I dry hopped with 31g of Mosaic. Then the fermentation went berserk 3 days later it had dropped to 1.005 and I dry hopped again with another 31g of mosaic. It’s now 13 days in and seems to have finished at 1.004 ! There are no off flavours or funky aromas the beer tastes a little bit thinner and harsher than usual but apart from that it seems OK not one to rave about though.
This has resulted in a beer with an ABV of 4.7% with an apparent attenuation of 90%
My predicted numbers were :-
OG 1.038
FG 1.007
4.1% ABV
Anyone shed any light on why my FG is low?
I am confident in my hydrometer readings.
Sorry it’s so long winded but I thought I would supply as much info as possible
Hi Mash Monster, i would be interested to know the profile Gash used, i have the occasional not hitting the numbers with my brewzilla 35 and i can't figure it out
 
I don't know, but I've never had a beer go anywhere near that low in 250 brews, many using that yeast. I'm tempted to say re-check it but you say you're confident in the readings, have you put the hydrometer in water to see if it's calibrated to 1.000?
Yep I have 3 hydrometers and they all read within 0.5 of a point they are all showing a FG of 1.004 🥴
 
90 percent is indeed very high attenuation. Could you share the malt bill and mash temperatures?

Possible causes could be hop creep (enzymes in hops leading to overattenuation) or perhaps a diastaticus in your fermenter. Could you tell us a bit more about which yeasts you have been using recently (Belle Saison is an often used diastatic yeast).
 
Sounds like it could be "hop creep", I've had it a few times when dry-hopping beers, and more frustratingly it doesn't always happen to the same beer and same setup.

From what I've read on the issue it depends on the way the hops you used were grown, sometimes they can contain higher levels of enzymes that break down normally unfermentable sugars in the beer which causes it to ferment out more than usual.

Depending on strain of yeast and temperature when the hops were added this can also produce off flavours but almost always results in a higher FG than intended and a thinner body beer.

interesting rabbit hole to do some research on.
 
3.42kg Clear choice Extra Pale
360g. Wheat malt
100g. Carapils
I used US -05 yeast
Mashed for 60mins @ 65-66°c

The penny has dropped I’ve Just checked the fermenter to see what yeast has been in it (I have half a dozen) and it has a large ‘W’ on the side which means it’s the one that SHMBO uses for her wines !!!!! Could this be my problem ??????
 
Sounds like it could be "hop creep", I've had it a few times when dry-hopping beers, and more frustratingly it doesn't always happen to the same beer and same setup.

From what I've read on the issue it depends on the way the hops you used were grown, sometimes they can contain higher levels of enzymes that break down normally unfermentable sugars in the beer which causes it to ferment out more than usual.

Depending on strain of yeast and temperature when the hops were added this can also produce off flavours but almost always results in a higher FG than intended and a thinner body beer.

interesting rabbit hole to do some research on.
This makes sense the fermentation went off like a rocket after the dry hopping 👍🏼
 
Sounds very much like hop creep. But don't worry too much about it. A low FG isn't a problem and the beer will taste very similar. I have a feeling that unless you were really _really_ looking for it, you probably wouldn't notice much difference between a beer that finished 1.004 and one that finished 1.010.

My latest brew using Danstar Belle Saison finished at a ridiculously low 1.003 (the lowest I've ever seen - that yeast is a monster!) and to be honest, I couldn't really tell when I cracked the first bottle last night. It still tasted very much like beer and didn't taste "thin" at all. The one thing it didn't have was a sweet residual taste in the mouth and was nice and refreshing (it also meant I drank it a lot quicker).

I've similarly had a few beers that finished at 1.020 (starting from about 1.045) and I have no idea what happened with it. Those ones still tasted like a good beer and had I not known it finished at 1.020 I probably wouldn't have even noticed. It did leave me feeling fuller as if I'd just filled up on bread though.

So in short - FG doesn't affect the finished beer as much as you'd think.
 
The penny has dropped I’ve Just checked the fermenter to see what yeast has been in it (I have half a dozen) and it has a large ‘W’ on the side which means it’s the one that SHMBO uses for her wines !!!!! Could this be my problem ??????
Only if you didn't clean/sanitise it properly and left some wine yeast in there that grew and attenuates higher than the ale yeast. But to be honest, I think it's more likely hop creep
 
Only if you didn't clean/sanitise it properly and left some wine yeast in there that grew and attenuates higher than the ale yeast. But to be honest, I think it's more likely hop creep
Much appreciated
Whilst I can’t be sure about cleaning and sanitising of the fermenter I am pretty anal about cleaning everything again and again so I will go with hop creep Thankfully that was the last of the Mosaic hops so fingers crossed it won’t happen too frequently in the future
 
Hi guys I’m not sure what’s happened to the YT link of the suggested profile by Gash.
When I originally posted the link it worked for me on both occasions but now it no longer works I’m sorry I don’t understand why
 
I have been having a fiddle with it going off what he does in the video, this may take some time i try it on my next brew
Looks like you have found the TY video I just used the link in the description and copied the recipe into Brewfather and then created a new profile from there.
I would be interested to hear how you get on. Good luck 🤞🏼
 
Back
Top