Incomplete/Stuck Fermentation?

[mopowers]

My fiancé and I have been homebrewing for about 3-4 years now and have about 30-40 batches under our belt. Fermentation of our most recent batch (MoreBeer all-grain Pliny clone) seems to have stalled a tad. We had a OG of 1.079 (a bit higher than expected), but after two weeks, has stalled at 1.024 after testing three days in a row.

We mashed at 149* and fermented for a week at 67* before raising to 70* for a week. We pitched a 1.6L starter of WLP090 (San Diego Super). The yeast was a 4-5th generation though. When we make starters, we usually make more than we need and pull ~400mls for our next starter.

I would've hoped for an FG more closer to 1.015-ish. This one just never got the krausen we typically get with WLP090. Does anyone have any ideas how to get the gravity down to 1.015-ish??? Would it be worthwhile to toss a pack of US-05 in and raise the temp to 72*?

Thanks!!!

 

[ajm163]

if you mashed at 149 i would expect that this would end dryer than 1.024. how reliable is the temp reading on your mash tun? if that is off by 3-4 degrees that might explain some of this. I would say give it a couple more days if it doesn't move than i would toss in 2 packages of US05 and keep it at 70 for a few day at least. if it still stays at 1.024 at that point i would say its done.

 

[mopowers]

if you mashed at 149 i would expect that this would end dryer than 1.024. how reliable is the temp reading on your mash tun? if that is off by 3-4 degrees that might explain some of this. I would say give it a couple more days if it doesn't move than i would toss in 2 packages of US05 and keep it at 70 for a few day at least. if it still stays at 1.024 at that point i would say its done.

Thanks! I just checked my digital instant read thermometer with another one and they both read the same. It also read right at 212 when I tested it with boiling water. I'm pretty confident that the mash temp was truly 149. Plus, I've never had this issue before either. I tossed a packet of US05 in earlier today and there seems to be action. Some new bubbles on the surface and the airlock is bubbling again. Hopefully it continues!!! Thanks again!

 

[mopowers]

So, I ended up tossing in a pack of US05 and bumping up the temp to 72*. Four days later, the gravity has stalled at 1.020, so it did drop four points. I wish we could get it a few points lower. Would it be worth making a new starter and tossing it in at high krausen, or maybe adding some enzyme???

 

[NTexBrewer]

Throwing out some other things to check.
Did you remember to add the 1lb of sugar?
Have you calibrated your hydrometer?
Are you using the same hydrometer for both the OG and FG?

Have you tasted it yet? It may taste fine and you are worrying about those last few gravity points when it may not matter. You are sitting at 75% attenuation and 7.73 ABV. Which is within the specs of the yeast.

 

[mopowers]

Throwing out some other things to check.
Did you remember to add the 1lb of sugar?
Have you calibrated your hydrometer?
Are you using the same hydrometer for both the OG and FG?

Have you tasted it yet? It may taste fine and you are worrying about those last few gravity points when it may not matter. You are sitting at 75% attenuation and 7.73 ABV. Which is within the specs of the yeast.

I did add the lb of sugar with 5 mins to go in the boil.

I have not calibrated the hydrometer but I did use the same one for all readings. This is a good point! I will check it for sure.

I have tasted it. It still needs the dry hop additions, but it tastes decent. A little sweet for my taste, but it is what it is I guess. Who knows, maybe the hydrometer is reading a few poinnts high. The OG was higher by 4 point than what it should've been. I think it's just done though. 75% is on the low end of attenuation for wlp090, but I'm sure it'll drink the same. I appreciate your input! Thank you!

 

[ajm163]

My guess is it is what it’s going to be. You have already re-pitched yeast so I don’t see doing it again is going to do anything. I would give it 2-3 more days if the reading is the same then package. If your keging you could do it now. The three days is more to avoid a mess if it is not 100% done if you are bottling

 

[mopowers]

Throwing out some other things to check.
Did you remember to add the 1lb of sugar?
Have you calibrated your hydrometer?
Are you using the same hydrometer for both the OG and FG?

Have you tasted it yet? It may taste fine and you are worrying about those last few gravity points when it may not matter. You are sitting at 75% attenuation and 7.73 ABV. Which is within the specs of the yeast.

Well, you nailed it! Turns out my hydrometer is reading 5 points high. I tested it in 60* distilled water and it read 1.005. I double checked it with a lab grade hydrometer with the same results.

That means this beer started at 1.074 and finished at 1.015. That's almost much exactly what beersmith says it should've been. Thanks again for the help!!!