Just kegged a pale ale that I had 52% attenuation, which is my 2nd batch in a row with poor attenuation. The first batch I brewed a cream ale 80% 2 row and 20% flaked corn. Mashed at 150. SG 1.050 with a target FG of 1.009. The actual FG of 1.016 for 67% attenuation. I used San Diego super yeast 090. I used a starter and pitched @60 degrees. I generally ferment low. I use a heat wrap and set it for 61 degrees. I tape a temp probe on the outside of the carboy and cover with bubble wrap and tape. The first batch I just chalked it up to whatever. However, I just kegged a 2nd beer that I mashed @152 with a SG of 1.052 and the FG was 1.024. I was shocked so I checked the hydrometer with water and it was properly calibrated. I’ve never had an issue before so I don’t pull gravity readings until I keg. I do pull small taste samples. Surprising both beers are good and don’t taste overly sweet or sweet at all really. I’ve never had issues with Attenuation and follow the same process. -pitch yeast @60 -ferment @61/62 -slowing raise temp after 48/72 hours until 68 degrees. I leave it at 68 for a few days - I don’t use oxygen, I just shake the crap out of the fermenter before pitching the yeast -I use brewchiper to calculate my pitch my pitch rate. Also, the 2nd batch I repitched the harvested yeast from the first batch. Wlp090. -Could this be a yeast issue or a process issue? -I used to use pure oxygen then stopped but haven’t had any issues -I harvested the yeast again as I was planning to pitch the same yeast for a double ipa but now I am concerned i’ll get poor attenuation and end up with a bitter pale ale. Should I just buy new yeast for my next batch? -should I increase the temp? Cheers
I’ll also add that I use brewcraft’s yeast nutrient. I build my water from RO but both batches had over 50ppm of calcium. The batch before this I brewed a porter with repitched 001 and went from 1.80 to 1.019.
As mentioned above, check your thermometer to ensure you are hitting your (actual) desired mash temps. My vote is just "faulty" yeast. I had that once before with a lager strain that two beers in a row didn't reach the minimum attenuation levels for that strain (low 60's). Yet the recipe, process, etc… Should have resulted in a very fermentable wort. Pure O2, low mash temps, mostly base malts, etc… My beers always tend to over-attenuate, so having one under was strange to me… Let alone two in a row. When I switched to a different lager yeast, all was back to normal. Those were the only two beers out of 50 or whatever that ever under-attenuated to this day. I would just dump that yeast and get a new vial/pack, honestly. All else sounds fine in your process, from what we know. The yeast is the easy thing to rule out by just getting a new one. Also, perhaps ferment warmer, too. It could be the strain really doesn’t like your cool temps, in terms of reaching attenuation levels… Data sheet says 65-68F. Also, check the calibration on your fermentation thermometer, as if that is off by a few degrees you may actually be sub 60F, which just may be too cool for that yeast.
Ya it must be your thermometer or your hydrometer. With that yeast strain I doubt you have that attentuation especially with your simple grist.
I have had low attenuation problems with the last several batches as well. Glad you brought this up. I will definitely be checking accuracy of my mash thermometer before brewing again -- it's probably reading too low, resulting in a hotter mash that is killing my beta amylase too fast. On the other hand... I've also been using English yeasts lately, so there's that as well.
I use an instant read thermometer but on my 2nd batch it was acting up so I used a different thermometer that isn’t a digital instant read, so that could be an issue for sure. That thermometer has been sitting in a drawer Years. I don’t use it much because of the instant read digital one.
Thanks. A lot of good options. I’ll pick up a vial of my favorite ipa yeast, WLP007 or a pack of imperial yeast since my LBHS just started using that. Then work on the other options such as possibly adding a thermowell instead of taping the proble to the carboy, and make sure my trusty digital instant read thermometer is working and calibrated before brew day. Cheers.
