Potential causes for a high FG?

[Stevorino]

I brewed Jamil's Blonde Ale Recipe (Slated to have an OG of 1.050 and FG of 1.009). When I brewed it, I had an OG of 1.054 and a FG of 1.019. So I'm trying to figure out what could make it so far off. I use a temperature controlled fridge w/ a thermowell. I'm 110% sure it fermented out completely -- it has been on the original yeast cake for nearly 25 days, during which I raised it to 70+ after the first week.

Here are things I am thinking could have gone wrong:

1) I used Jamil's calculator to decide how much starter wort to use -- when doing so, I calculated it for a 5 gallon batch of 1.050, not a 5.5 gallon batch of 1.054 -- but would that insignificant of an underpitch really make a big difference?

2) I pitched a tad warm (4-5 degrees).

3) My thermometer broke during my mash, so it is possible that I mashed quite a bit higher/lower than recommended by Jamil's recipe instructions.

4) A little bit of yeast got into suspension in my Hydrometer Flask -- but that wouldn't cause a difference in reading, right?

-- Thanks guys, I aim to fix all of these mistakes going forward in my process -- I'm just wondering what happened here -- Tastes fucking good though going into the kegs!

[BigNastyBrew]

I brewed that and it finished a little high, if I remember. Could be the yeast strain, too. DOn't exclude that.

[BigNastyBrew]

Oh.... have you calibrated your hydrometer with distilled water? Mine is 1.003 at 60°. So, I have to subtract 3 points from every reading I take.

[ApresSkiBrewer]

Calibrate your hydro for sure... but if you mashed 3-4 degrees higher it could also be an issue w/ your wort fermentability. How does it taste?

Also, what did you do for oxygenation?

[Stevorino]

I have two hydrometers -- just calibrated both and they were perfect. I tried both last night and they agreed.

I used an oxygen tank and stone for oxygenation - swirled it around a little over a minute until the foam was bubbling out of the carboy.

And I used WLP001 - Attenuation range between 73 and 80% -- Promash is calculating mine at 63%.


It tastes fantastic -- maybe my best tasting beer pre-carbonation. I actually thought it was pretty dry too until I realized what the FG was and then started to think it was a tad sweet, but not much. It's hard for me to tell w/o carbonation what it's body is -- but it tastes pretty thick (which I realize would be a product of a high mash temp/non-fermentables).

So I guess right now I'm leaning towards thinking I just had a very high mash temp -- but is that capable of adding another 10 points to my FG?

[summy]

It's good that you kegged it instead of bottling it. Could end up with a bunch of gushers if you'd have bottled it...

[Hoppy Brewah]

John Palmer has a good article about attenuation in this month's Brew Your Own. At what point in the mash did the thermometer break - did you get any good readings? Perhaps a back up lab thermometer would be a good idea. I don't know if that alone would cause a 10 point increase in FG, but probably 5 points there and 5 points in the yeast/ fermentation. I just made an amber ale with crystal 80 and 120 and some pale chocolate malt, mashed at 149 - trying to get some sweetness from the specialty malts and a dry finish to accentuate the hops.

[Stevorino]

We'll see how it tastes after carbonation -- sounds like I didn't miss anything critical that I just overlooked, which is what my main concern was.

I'll let you boys know how it turns out. Thanks for replying!