Poor Attenuation in My Last Three Batches

[hollywoodbrew]

Since my son was born, I’ve been brewing a lot less these days. After about a six month hiatus, I started brewing again. Unfortunately these last three batches since hiatus have had really poor attenuation. I’m not sure how to address it.

The first batch (#1) was Jamil’s Amber Waves, tasted like ****. I mashed at 154F and it finished at around 1.017, I chalked it up to the high mash temp. I never usually mash that high. So I dumped it.

Then I brewed a Kaiser Alt (#2), this is a beer that I’ve brewed a few times with great results. I hit my marks perfectly, mashing at 150F, starch test passed, etc. The only thing that went wrong was I had I surprising efficiency boost, and I decided to not adjust the OG. So this one went from 1.054 to 1.015. WY1007 is supposed to be highly attenuative, and the beer is still cloudy with yeast 4 weeks in. It should really be down to at least 1.011 if not lower. Every other time I’ve brewed this batch it went from about 1.049 to ~1.009

My final batch (#3) was a personal Pale Ale recipe that I’ve honed in over the years. Mashed at 152F, confirmed conversion with the iodine starch test, this recipe even uses 60% maris otter. This time I used the conan-based Vermont Ale Yeast. This one went from 1.059 to 1.015. It’s only two weeks in, but the yeast has completely flocked out.

All batches were fermented at 66-68F for 4 days then ramped to 72F, pretty standard for me. What can I do to fix these batches? I’m really tempted to try a pinch of beano. I’ve already tried the waiting game, a month in primary for #1 and #2. Last night I pitched S-05 dry yeast into the alt (#2) and pale (#3), hoping that would do the trick. I’m really bummed, and I can’t tell if it’s the mash or the fermentation that is the problem. For the record I also checked my hydrometer which reads 1.000 in tap water.

This has never been a problem for me until I took that hiatus. Any ideas on how to get my brewing back on track? The only thing I can think of is that I'm getting false results on my iodine starch test. Can I conduct this test on finished beer?

 

[m00ps]

Have you just been using those dried yeast packets without rehydrating or a starter? You may just need more yeast to begin with and you are stressing the yeast too much so they tucker out.

Also, did you aerate the batches when you pitched?

edit: nevermind, just saw where you said you used Conan for one of them. Conan's always hit around +80% for me. Hmm...I'd guess that maybe you thermometer is miscalibrated so you've been mashing a bit higher than you think

 

[d3track]

Verified your thermometers aren't off?

 

[hollywoodbrew]

Verified your thermometers aren't off?

This is a good point, and would explain a lot. However the iodine test passed at the end of the mash (though I could have been doing it wrong).

I haven't, but I just broke the thermometer I usually use. So now I have a new digital and a new glass thermometer for the next batch. I will calibrate in ice water next time.

Do you know if the iodine test works on beer? Or will the alcohol mess up the results?

 

[hollywoodbrew]

Also, did you aerate the batches when you pitched?

I do aerate, I dump the wort from the kettle into the carboy (I've been told that's plenty aeration for medium gravity beers.) However I give a good 30 seconds of shaking too! Maybe that's not enough? The three fermentations have all started like a rocket, blowoff was required. WLP001, WY1007, and WLP4000, all were pitched using decent starters.

 

[hollywoodbrew]

Conan's always hit around +80% for me.

Do you do anything special for Conan? Like mashing lower or adding sugar a few days in? I have seen these recommendations, but ignored them for my first try.

 

[peterj]

This is a good point, and would explain a lot. However the iodine test passed at the end of the mash (though I could have been doing it wrong).

I haven't, but I just broke the thermometer I usually use. So now I have a new digital and a new glass thermometer for the next batch. I will calibrate in ice water next time.

Do you know if the iodine test works on beer? Or will the alcohol mess up the results?

If your thermometer was just a few degrees off and you mashed higher than you thought, you'll still get complete conversion and the iodine test will still be passing. But you will have produced a less fermentable wort with more dextrins than you wanted. Sounds like this could be your answer. Are there any other factors that have changed? Water source, equipment, etc.?

 

[ricshayne]

Maybe the thermometers.....
Do you use Campden tabs? Ive heard that using too much will cause poor attenuation.
If all else fails you could always just mash longer to allow the sugars to become more fermentable.

 

[hollywoodbrew]

...you'll still get complete conversion and the iodine test will still be passing. But you will have produced a less fermentable wort with more dextrins than you wanted.

This is interesting, I didn't realize this is how it works. Come to think of it I remember reading boiling water at around 206F at sea level. I sort of thought that's to be expected, no one ever measures 212F exactly right? But, if that's taken into account, worst case, I could have been mashing at 144-146F. Too low?

No changes have been made to my equipment for about 30 batches.

 

[hollywoodbrew]

Do you use Campden tabs? Ive heard that using too much will cause poor attenuation.
If all else fails you could always just mash longer to allow the sugars to become more fermentable.

I build my own water from RO, so I don't need campden tablets. But I think I will use a longer mash next time. Also I'll use two thermometers, calibrated to ice water.

 

[peterj]

This is interesting, I didn't realize this is how it works. Come to think of it I remember reading boiling water at around 206F at sea level. I sort of thought that's to be expected, no one ever measures 212F exactly right? But, if that's taken into account, worst case, I could have been mashing at 144-146F. Too low?

No changes have been made to my equipment for about 30 batches.

Yeah I think it's definitely the thermometer then. It should read just about 212F at sea level.

And if it's reading 6 degrees lower, then when you mashed at 150F the actual temp was 156F. And 154F was actually 160F.

 

[blizz81]

I'm on board with the thermometer, given the rest of the details in the process.


I still can't believe something at 1.015 needs fixing though and / or that you'd dump the first one! I guess for some super-dry styles it might play more, but I'd probably shrug and drink something with no qualms if it hit 1.015 instead of 1.010. You could try something more aggressive than S-05 - at least they seem low-gravity enough-type beers that alcohol tolerance shouldn't be a big worry, but S-05 might just feast on the same simple sugars that have already been eaten if indeed your therm is off and you mashed higher.

 

[blizz81]

This is interesting, I didn't realize this is how it works. Come to think of it I remember reading boiling water at around 206F at sea level. I sort of thought that's to be expected, no one ever measures 212F exactly right? But, if that's taken into account, worst case, I could have been mashing at 144-146F. Too low?

No changes have been made to my equipment for about 30 batches.

Just saw this after I submitted. Too low would yield a more fermentable wort.

 

[ricshayne]

also man, I just had a son as well, and Ive found that scaling down and doing 2.5-3 gallon batches inside on the stovetop really makes things a ton easier.

 

[hollywoodbrew]

Just saw this after I submitted. Too low would yield a more fermentable wort.

I am dumb, peterj is right. That would mean HIGHER mash temp. I had that backwards. So, likely I've been mashing at 158F, which could explain everything!

 

[peterj]

Maybe the thermometers.....
Do you use Campden tabs? Ive heard that using too much will cause poor attenuation.
If all else fails you could always just mash longer to allow the sugars to become more fermentable.

Mashing for longer won't really have an effect on the fermentability. It's all about the temperature. The only reason to mash longer is if you're mashing at a lower temperature it will give the enzymes more time to convert all of the starch because reactions proceed slower at lower temperatures.

 

[blizz81]

Mashing for longer won't really have an effect on the fermentability. It's all about the temperature. The only reason to mash longer is if you're mashing at a lower temperature it will give the enzymes more time to convert all of the starch because reactions proceed slower at lower temperatures.

I agree - there's a following out there to the "mash longer = more fermentable wort" (ie, sticky in this forum), but I think people lose more temp and / or simply take one temp reading from one spot in the top of the mash and don't realize they're losing more temp (possibly around the outsides in the whole mash, etc) the longer they mash, and connect the dots because of it.

 

[hollywoodbrew]

also man, I just had a son as well, and Ive found that scaling down and doing 2.5-3 gallon batches inside on the stovetop really makes things a ton easier.

Congrats! I figured out a way to fence off my brewing area so the kid can hang out with me while a I brew. I used a playpen fence, but instead of putting the kid in it, I put my brewing setup in it. My wife really doesn't like when I brew in the kitchen.

 

[hollywoodbrew]

I just pulled the trigger on the ThermaPen! They are discontinuing British Racing Green, so I got it for $79. No more inaccurate readings!

 

[m00ps]

Do you do anything special for Conan? Like mashing lower or adding sugar a few days in? I have seen these recommendations, but ignored them for my first try.

Not really, I've used it at different temps, but I like the mid 60s the best. Once I had it going in the high 50s and it did alright. I harvest yeast from all my starters to save for the next brew. Conan seems to get stronger with each generation. Its definitely fermented some of my beers past 80% with my 3rd and 4th generations

 

[hollywoodbrew]

I purchased some amylase enzyme yesterday from my LHBS put a teaspoon into each fermenter and today the airlock is bubbling! Now I just need to keep an eye on the SG and make sure it doesn't go too low. When it reached the desired FG, I will cold crash with gelatin to drop the yeast.