Beer will not attenuate properly

[jfkriege]

I was making an ordinary english bitter, and the fermentation stuck. OG was 1.039 and the FG was meant to be 1.011.

The ferment stuck at 1.029 because my wife dropped the temp to 60F. I warmed it back up to 68F and stirred it up, then raised the temp over a few days to 71F. It came down to 1.026 over 10 days.

I then made another starter with WLP002 English Ale Yeast and repitched. It has been at 70F for a week now and it is now down to 1.021, and the last three days have been at 1.021.

I am thinking that I should just keg it and see what happens. It tastes decent, but perhaps a bit sweet. The sweetness might just be that it is uncarbonated.

What do you think?

 

[android]

you should get better attenuation than that... is this an extract batch, partial, all grain?

 

[jfkriege]

It was an extract batch.

I have used the yeast before and have never had an issue with attenuation, so this one has me a little baffled.

The only thing I can think of is that I had a little kettle caramelization, but I have trouble thinking that would account for that big a difference.

 

[shortyjacobs]

Someone's gonna ask, so I might as well be first: you sure your hydrometer isn't effed up? Stick it in some distilled water and see if it reads 1.000

 

[jfkriege]

I am using a refractometer, and I have ensured calibration for it twice. I totally understand why you ask though, I would have done the same.

 

[scinerd3000]

generally a hydrometer is used when there is alcohol in the solution because it will throw off the refractometer brix reading unless you have one setup for that. Someone once told me that there is a conversion formula you can use to correct the refractometer but i always just use a hydrometer so you may want to compare readings and see what you get.

 

[jfkriege]

You sir, are a rockstar. That was exactly the information I needed. The reason that I didn't pick up on it earlier is that this is the first batch that I have used the refractometer on for final gravity. I now remember reading that somewhere, but it just got pushed to the back.

A calculator can be found here that accounts for the change in refractive index due to alcohol by using the OG reading:
http://onebeer.net/refractometer.shtml

It turns out my FG is not 1.021, but actually 1.010, right where it should be. Now, off to keg......

 

[oldschool]

I wish all issues are that easy to solve

 

[jfkriege]

I second that. Though I have been banging my head against a wall trying to get this right for 2 weeks. At least this one will never happen again.

 

[scinerd3000]

I second that. Though I have been banging my head against a wall trying to get this right for 2 weeks. At least this one will never happen again.

we've all been there

 

[david_42]

I think this is the #2 instrument problem after, "OMG! Where did my CO2g go?"

 

[Mpez]

OMG! I was just about ready to dump a batch that would not finish!

This thread saved my beer!