Newbie Question — Low FG

[Texas]

Well..... Newb doing 1 gallon batches.
I brewed a batch of amber lager . Used Mangrove Jack’s Californian Lager yeast. Took maybe 12 hrs to get rocking and went on for 3 days if IIRC. After about 9 days I checked the FG was 1.022 and OG was 1.068.
It was pretty sweet. We noticed it was bubbling after moving it for bottling, so we put the stoppers back on. I swirled it again and it really bubbled up. Haven’t touched in past 4 or 5 days.
Any thoughts?

 

[RM-MN]

Fermenting beer dissolves an excess of CO2 into the beer, more than it can hold for a long period. Moving the fermenter causes it to outgas. Your beer should have been fully fermented by the 9 days.

 

[Texas]

Thank you. I just didn't know if has something to do with the lager yeast vs. ale yeast. I'll try again this week. If still too sweet I'll have to dump. Luckily I'm only making 1 gal batches.

 

[MrHadack]

The OG and FG numbers you posted give an estimated ABV of 6%. Seems like pretty solid fermentation happened here. What were you expecting to hit for FG and ABV according to the recipe?

Also, as a comment: sweetness in beer doesn't necessarily mean fermentation isn't done. I saw in another thread you posted questions about mash temps, and I address this in more detail there. But if you did a mash for this beer, and the temp of the mash was in the higher end of the range (say, 155-158F) you will have created a lot of sugars which are not fermentable and simply add body and sweetness to the beer.

Also, to know if fermentation is done, wait a week or two, and then check the gravity. Wait another 3 days and check it again. If it's close to where you expected it to be, and it doesn't change in those three days, it's done. If it is still dropping, it isn't. Air bubbles are not a reliable indicator, as noted by RM-MN in this thread.

 

[Texas]

Sorry OG=1.063 so 5.38% ABV. The yeast is high attenuation. So I would expect < 1.02

 

[MrHadack]

Sorry OG=1.063 so 5.38% ABV. The yeast is high attenuation. So I would expect < 1.02

I looked up the yeast you used, and there are no specific attenuation ranges posted, it just says "High." So I looked up a comparable yeast on the White Labs site (WLP810, California Lager) and it says 65-70%. With a current ABV of 5.38% I assume your current gravity is something like 1.022. That would give you 64% attenuation, which is at the low end of the expected range. So it isn't too bad at all.

The next question is probably "why is it on the lower end of the range, though?"
If you did a mash, and the temp was too high, you will have created more sugars which are unfermentable. That would be reflected in a lower attenuation. Other mash factors can affect this as well such as pH.

 

[Texas]

Thank you, this some really great info.

 

[RM-MN]

You didn't mention the temperature during the fermentation. Some yeasts will go dormant before the expected attenuation if the beer is too cool. Warming the beer at the end can cause the yeast to attenuate more.

 

[Texas]

You didn't mention the temperature during the fermentation. Some yeasts will go dormant before the expected attenuation if the beer is too cool. Warming the beer at the end can cause the yeast to attenuate more.

Both were average of 66F, 67F

 

[Texas]

So an update. I swirled both about 5 days ago. Check FG today and dropped 2 - 4 points. However, they smell like ethylene glycol perhaps and taste sweet and well almost undrinkable. Any chance they recover... or is time to dump? They’re only 1 gallon batches... so not a huge loss. They both were pitched with Mangrove Jack California Lager yeast.
On an upside I brewed a quick batch last Friday of a dark ale / stout. Used MJ New World Strong Ale. Tested it also. OG=1.058 FG=1.016. Smelled like beer, tastes like a dark ale, stout, coffee. I ill bottle that in the next coupple of days. That will be nice. It’s mild brother I made a few weeks ago has been a good session beer.
I was hoping to have the 2 lagers bottled but I guess I may need to brew another ale this weekend.

 

[FatDragon]

If I remember right, your kits have a pretty high percentage of crystal malts, which may contribute a lot of unfermentable sugars. That could be part of the issue.

 

[Texas]

The beer got infected for sure — I se what appears to be mold on the top of one. Not sure why 2 different batches got infected but oh well. I’ll be more careful next time.

 

[FatDragon]

Are you sure it's not krausen? Maybe post a picture.

 

[Texas]

 

[MrHadack]

From those pics I'd say not infected, and pretty normal looking. I think you're ok.

When I get infections they usually look like a thick layer of fluffy cobwebs over the surface of the beer, but infections can take different forms. Even still, in the past I have siphoned the beer out from under that layer and bottled it. It came out fine.

 

[FatDragon]

Pic 1 looks fine, maybe a bit of hop oils floating on the surface of the wort. Pic 2 looks like leftover krausen at the end of fermentation.

 

[Texas]

Hmm. it has that sickenly sweet moldy bread or food smell. The second still has bubbles coming up occassionaly from the bottom. I’ve moved them to a slightly warmer part of the house in the past day because I was going to dump them.
Just what I tested wasn’t very beer-like.

The first one looks almost like it’s separated with this watery layer on top and another layer below.

 

[FatDragon]

The separation sounds like yeast and trub flocculating out of suspension, which is good and normal. Continuing to bubble could be continued fermentation or CO2 off-gassing, both of which are also normal. My advice: bottle them once they reach 2+ weeks and forget about them for another 2-3 weeks (if you're worried about infected beer, put the bottles in a plastic tub with a towel over them in case they explode), then chill one from each batch and try it. If it's clearly gone bad, you can go ahead and dump the rest, but you'll probably find that they're fine and your current concerns are just normal new brewer nerves.

 

[Texas]

Ok before I saw that last comment i pitched teh rest of yeast and swirled / shook them again. Then I saw your message so I left them for the past several days and bottle them tonight.
Had a little taste and they’re getting better but probably not “drinkable yet’. I’ll let them set and we’ll see what happens!
Thanks for the advice.

 

[kh54s10]

If they are getting better, but don't taste "drinkable yet" - don't bottle them.

Leave them for at least a few more days and taste again. They should taste OK, like flat warm beer. Sometime they will not taste really good, but after bottle conditioning they might change quite a bit. From OK to pretty good. I would say that bottle conditioning will not take a Bad to good, though.

 

[Texas]

Just to check-in... the beer is pretty bad. On the plus side I picked up John Palmer’s Book in Hong Kong this past week and figured out that I did several key things wrong with the lager. I guess lagers are much more finicky than ales.
On the flip side the dark ale I did a month ago really mellowed and is great.