Final gravity on a hefe-help!

I'm a new all grain brewer and this is my first post. I've been browsing and reading quite a bit, and I think I've figured out what I'm doing wrong, but I still wanted to seek out the wisdom of experienced brewers. The same thing happened on my first two AG batches, both hefes, same recipe. Issue is FG is way too high. I'm going to try for a third batch this weekend and don't want to mess that one up too.

On most recent batch OG is on target at 1.055. Final is stuck at 1.032. It's been that way for over two weeks. Ferm starts strong-learned the hard way why blowoff tubes are used. I use wlp380 and pitch at 54, raise temp to 63 for the duration.

In the first batch the same thing happened (high FG). After four weeks I gave up and bottled with speise. The taste was really (surprisingly) good but extremely low on alcohol.

I think the yeast is fine because of the visual evidence of fermentation. My suspicion is that I'm not hitting my mash temp and getting a lot of unfermentable sugars. I use a digital thermometer but I get different readings all through the mash. And I wonder if I'm too impatient in letting the mash stabilize and should be stirring more to reduce hot spots. I mash in at 111 and apply heat to hit 152. Or at least that's the goal.

Could the temp be the culprit? Am I missing something else? Would an iodine test tell me whether I've got fermentable sugars in the pot?

Thanks very much for the advice.



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Yes, the mash temp could be the culprit. You are also pitching/fermenting quite cold for this yeast. 2 questions:

-what method are you using to apply heat? Direct fire? If so, are you recirculating while heating? If not, you could be denaturing the enzymes locally where the heat is being applied.

-what is the reason for the low pitch temp? 63 is probably fine as a primary temp (a bit low, but some advocate this, notably Jamil Z.) 54 seems very low for a hefe pitch temp, though.

Yes, I'm using direct fire. But I'm not recirculating. Or haven't been. Sounds like that may help.

A buddy I brew with found the recipe on the Northern Brewer forum. That one recommended pitching at a low temp.

Thanks for the ideas! If recirculating might help I'll definitely try it!


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What yeast strain did you use and what is the ideal temperature range for that strain? More than likely you are just fermenting too cold.

It's ok to keep the temperature slightly below the recommended range during the vigorous first couple days of primary, since the active fermentation increases the temperature of the wort by 2-4 degrees. After that however, you need to raise your temperature to within the recommended temperature range of the yeast to help it finish out.

Conman13 said:

What yeast strain did you use and what is the ideal temperature range for that strain?

Click to expand...

He used WLP380 so 63 is slightly below its recommended temp range, but should be fine. I would pitch at that temp as well (63, not at 54).

I suspect that the lack of recirculation is your main issue though, raising the mash temp 40+ degrees via direct fire without recirc is likely bringing the lower part of your mash well above the target temp and could be denaturing the alpha & beta enzymes.

I would also check mash pH, if you haven't already.

PS, you don't need to add recirc capability to address the temp issue. Stirring continuously during the temp ramp up should also do it. Or you could just eliminate the 111 step and do a single step infusion at 152.

Wilconrad, I can definitely recirculate. Easy actually. Like I said I'm new and was trying to dive into AG and familiarize myself with my system all at once. If I recirculate is there a increased risk of getting a stuck mash?

I'm positive the lower part of my mash was hotter than the top, probably greatly so. Is there any problem with raising the temp extremely slowly with a low flame? The ramp up times in the original recipe are short, or seem so to me. Heating my 10 gal - almost 19 lbs of grain - mash up takes a long time.




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By recirculate I mean continuously, with a pump. If you're setup to do that, then definitely do so while you're heating the mash. If you're not, stir continuously while you're applying heat.

As far as the risk of a stuck mash, you can cause a stuck mash if you recirc too quickly. In this case, since you've got wheat in the recipe, the risk of a stuck mash is higher. Whenever I have wheat, corn, or other huskless grain in my mash I add a lb of rice hulls to help keep the grain bed from compacting and maintain the recirc flow. You don't need a very fast flow, just enough to keep things moving in there so it doesn't get too hot.

I have a pump. Definitely will go slow. So far I've taken my time and haven't had a stuck sparge (no rice hulls added). It's been a big concern.

Thanks again!


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Are you using a hydrometer or a refractometer for your gravity readings?
If you are using a hydrometer, I cannot help.
If you are using a refractometer, you need to apply a correction to get an approximation of the true final gravity.
See http://seanterrill.com/2012/01/06/refractometer-calculator/ for one example of a calculator that estimates the FG.

-a.

Ajf, I use a BrewFractometer. The FG is so whacky I checked the gravity with that and with a hydrometer. Both came out the same.


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Are you using the reading directly from the refractometer to get your FG value, or are you processing the refractometer reading through some sort of calculator to get the FG reading?
If you are reading the FG as 1.032 directly from the refractometer scale, then the true FG will be approximately 1.017 (give or take a few points). This is because a refractometer reads the refractive index of a solution, and the refractive index of ethanol is higher than that of water, while the specific gravity of ethanol is lower than that of water. If you read 1.032 directly from the refractometer and got the same reading from a hydrometer, then at least one of the instruments is giving a faulty reading.
If you translated the refractometer reading to give you a FG estimate, then what calculator did you use?

-a.

Ajf, I see what you're saying now. No, I took the readings directly and didn't use any calculator. I'll do that in the future. The readings may have been close because there is so little alcohol in the beer. The content seems far lower than even a light beer. It's really that noticeable.


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