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Low Attenuation?

Northern Brewer General
#1

I’m currently fermenting a batch of Caribou Slobber and an Oatmeal Cookie Brown. I just racked the Caribou Slobber to secondary after 3 weeks in the primary, and after taking a gravity reading, it seems my attenuation was abnormally low. My OG was 1.058 and SG was 1.024. This seems a bit high for being in the fermenter for more than 3 weeks. I used the Danstar Windsor yeast, which doesn’t list an attenuation range (at least not on the NB site). According to Brewersfriend.com, this only attenuated to 56%. Seems pretty low, no?

The Oatmeal Cookie Brown has been in primary for 2 weeks, had an OG of 1.078 and a SG of 1.025. The attenuation on this one is only coming out at around 66%, using Wyeast 1945 Neo Britannia. This one seems a bit low as well, but I’m guessing it just needs a bit longer in the primary.

In any case, has anybody had problems with low attenuation with either of these two yeasts? Is there a common error that attributes to this? Any thoughts or feedback are appreciated. Thanks!

#2

Yes, I used Danstar Windsor in my Bourbon Barrel porter and my FG was around 1.025. OG was a little higher at 1.064 but its notoriously a low attenuating strain.

That being said, the beer is very tasty so I can’t really complain :slight_smile:

#3

Windsor is a low attenuator, so that could be part of it. But the bigger factor is the fermentability of your wort. If you make a wort high in unfermentables, any yeast will have trouble getting high attenuation.

#4

That’s good to know. I couldn’t imagine there were too many non-fermentable components in my wort, considering the batch of Caribou Slobber was a straight extract kit. I’m feeling reassured that the Danstar Windsor is notoriously a low attenuator. (I was getting nervous that I may have messed up what many consider one of the easiest recipes to make, and this is my second time making it!)

The Oatmeal Cookie Brown was an all grain recipe, and given it’s high initial gravity of 1.078, I’m assuming I’ll see it attenuate further with more time in the primary. Accurate assumption? I know the Wyeast 1945 should be somewhere in the 70% -77% range, which means I either have a stuck fermentation at 66%, or I just haven’t given it enough time.

#5

[quote=“S Wagner”]That’s good to know. I couldn’t imagine there were too many non-fermentable components in my wort, considering the batch of Caribou Slobber was a straight extract kit. I’m feeling reassured that the Danstar Windsor is notoriously a low attenuator. (I was getting nervous that I may have messed up what many consider one of the easiest recipes to make, and this is my second time making it!)

The Oatmeal Cookie Brown was an all grain recipe, and given it’s high initial gravity of 1.078, I’m assuming I’ll see it attenuate further with more time in the primary. Accurate assumption? I know the Wyeast 1945 should be somewhere in the 70% -77% range, which means I either have a stuck fermentation at 66%, or I just haven’t given it enough time.[/quote]

Extract, especially extract ts other than extra light, are notorious for having a higher than normal amount of unfermentables. When I designed extract kits for NB, I replaced part of the extract with sugar to get higher attenuation. BTW, if you’re using liquid yeast with a 1.078 beer, you’ll need to make a starter.

#6

[quote=“Denny”][quote=“S Wagner”]That’s good to know. I couldn’t imagine there were too many non-fermentable components in my wort, considering the batch of Caribou Slobber was a straight extract kit. I’m feeling reassured that the Danstar Windsor is notoriously a low attenuator. (I was getting nervous that I may have messed up what many consider one of the easiest recipes to make, and this is my second time making it!)

The Oatmeal Cookie Brown was an all grain recipe, and given it’s high initial gravity of 1.078, I’m assuming I’ll see it attenuate further with more time in the primary. Accurate assumption? I know the Wyeast 1945 should be somewhere in the 70% -77% range, which means I either have a stuck fermentation at 66%, or I just haven’t given it enough time.[/quote]

Extract, especially extract ts other than extra light, are notorious for having a higher than normal amount of unfermentables. When I designed extract kits for NB, I replaced part of the extract with sugar to get higher attenuation. BTW, if you’re using liquid yeast with a 1.078 beer, you’ll need to make a starter.[/quote]

Also very good to know, and surprising. I would’ve guessed otherwise, but thanks for the heads-up! I did make a two step starter for the Oatmeal Cookie Brown, so I know I pitched plenty of yeast. Had a good solid krauesen cap going on it for about 10 days before it finally subsided. I’ll check the gravity again next weekend and see where it’s at. I’m thinking if it hasn’t attenuated past 66% after 3 weeks, it may be a stuck fermentation?

#7

I’d say that more likely it’s finished rather than stuck.

#8

I’ve been having problems lately with low attenuation,too.And it’s been happening with a variety of different yeasts,and I’ve also been using yeast starters,and aerating the crap out of the wort.I think it’s just getting to be that time of year where the ground temperature is becoming an issue.I don’t know where you live,or what part of your house you do your ferementing in,but I live in Michigan,and I do my fermenting in the basement,where there’s a concrete floor.I think the problem is that the ground temeprature is having an effect on the fermentation vessel,even if the ambient temperature of the room is where it needs to be for proper fermentation.My solution from now on during the colder months is going to be to put the carboy on some kind of platform that isolates it from the floor.I can’t think of anything esle that I can really do to address this issue.I hope that sounds like useful advice.

#9

In my experience (which is admittedly limited) you’re usually pretty safe trusting your fermometer as to the temperature of the fermentation (+/- a couple degrees). Are you witnessing much lower fermentation temperatures than ambient temps?

#10

In my experience (which is admittedly limited) you’re usually pretty safe trusting your fermometer as to the temperature of the fermentation (+/- a couple degrees). Are you witnessing much lower fermentation temperatures than ambient temps?[/quote]

I too ferment in my basement, and in the upper Midwest. I keep my fermenters on a throw rug, so I don think the concrete temps are playing much of a role. The ambient temps have been pretty steady in the upper 60s and the fermenters have been holding steady at between 66 and 68. I don’t think the temps have been playing a factor, but I have noticed my latest few brews have been attenuating on the low side as well lately.

Not sure what it is, but now that I know extracts contain a bunch of non- fermentables (thank you again for mentioning that Denny!) I’m not as worried that I’m screwing something up. Looks like I’ll just have to start brewing more all- grain batches!

#11

In my experience (which is admittedly limited) you’re usually pretty safe trusting your fermometer as to the temperature of the fermentation (+/- a couple degrees). Are you witnessing much lower fermentation temperatures than ambient temps?[/quote]

I guess I’m not familiar with the “fermomemeter” you’re referring to.I’m assuming that must be a thermometer that’s somehow immersed in the wort or affixed to the outside of the carboy(?).I cannot say what the actual fermentation temperature is,but the ambient temperature is definitely in the mid-to-upper 60s,which should be suitable for ale fermentation,barring any other problems.Like I said,though,I really think that a concrete floor in a basement can be colder than what you might think,and that might very well be my problem (and possibly yours,too).

#12
http://www.northernbrewer.com/shop/fermometer.html

It’s one of those thermometers that stick to the side of your carboy. These usually pretty accurately tell you the temperature of your beer within a couple degrees. If your concrete floor is contributing to lowering the temp of your beer, you would see it reflected in that.

How are you currently checking the temp of your fermentation?

#13

I use the fermometers from NB on all of my carboys. I think they work really well, and are definitely a necessity as ambient temps and fermentation/beer temps vary by a few degrees.

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