Stuck fermentation

Ok so I'm sure the answer to my problem has been discussed before but I've never had this problem so I missed the answer. I brewed an classic American lager and after 3 months of fermenting and lagering, I have a fg of 1.020. I used white labs American lager yeast and pitched at 60 and decreased to 55. Then after 4 weeks, rested at 70. Then lagered down to 48 for 2 months. My sg was 1.070. Now, according to attenuation rates, it's close. But it tastes sweet. I'm under the impression this constitutes a stuck fermentation. Where do I go from here? Should I repitch?

You were high @ 1.070, 1.020 might be the best you get. How sweet is it? The style calls for a corn-like sweetness.

It's a little bit table sugar-ish. I kinda thought .070-.020 is about it but I was hoping for .010-.012

I'm thinking you would have had to start closer to 1.050 to get down to 1.010. What was your mash temp?

Single infusion 152. Well......perhaps I've figured out the problem. I think it's right where it should be now that I step back and look at mash temp and og. Maybe I'll just carb it up and see how it tastes.

I was shooting for 1.050-1.060. Ended up having 10% better mash efficiency than expected. That's where it got all screwy. Ok well I'll have to brew it again with less base grain and see if I can hit the mark.

I have heard some advocate a single temp at 148F to help dry it out.

This does not constitute a stuck fermentation. You said yourself you are in the expected attenuation range. How much yeast did you pitch?

It's done; carb it up, do better on the next batch. The first thing you have to do is pitch enough yeast at the right temperature. Then use your hydrometer to decide when to rest it, not your calendar--you want your SG to be around 1.020 if/when you move the temperature up (not everyone bothers with a diacetyl rest).

Lagers are not tricky if you just pitch enough yeast. Make huge starters as per Mr. Malty, or else just save yourself time, money and headaches and pitch dry yeast (or slurry) until you really get the hang of fermenting cool.

Good luck!

I pitched from the vial because I start at a warmer temp. I did check my gravity before rest and it was 1.028. Figured the yeast would consume the rest of the fermentables during medium temp rest. I was correct at that in it hit 1.020 to finish. Now, the og was higher than anticipated which is another reason why I didn't use a starter. I've brewed lagers before and had them spot on. This is the first time I've had an issue like this. Of course, I've always had an issue with water chemistry as well and got that fixed with this batch. So rebrewing a couple times should get me where I want to be I think.

Wouldn't having a higher OG be even more of a reason to make a starter than normal?

I have read that it is more important to do starters with lagers than it is with ales and that it is preferable to do so with ales.

mrmalty suggests for a lager of 1.070 to use 5.2 vials of yeast or a 2.55 liter starter using a stirplate.

If you pitched one vial I think any off taste could be attributed to this. But, 1.020 is probably about the best no matter how much yeast was pitched

5.2 vials???? Holy exploding carboy batman!!! My one vial lit off pretty hardy within 24 hours. And yes, I know a higher og requires a starter, but like I said I didn't anticipate an og that high. I was shooting for 1.050-1.060. Only had one vial, and I don't own a stirplate. Now as far as off flavors due to low yeast, that's a new one to me. I was under the impression yeast multiplied during fermentation.

brewmasterpa said:

Now as far as off flavors due to low yeast, that's a new one to me. I was under the impression yeast multiplied during fermentation.

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Before your next lager, look into proper pitching rates. Most brewers consider the pitching rate calculator at www.mrmalty.com a valuable resource.