Stuck Fermentation - 2 Batches - 2 Yeasts. Help!

Ok, so I went to bottle my porter this afternoon and found that it was stuck at 1.030 after 40+ days. What a disappointment. Never having this problem, I already had it in the bottling bucket ready to go and had to transfer it back into the fermenter to see if I can get anything to happen again! This beer started at 1.064 (9/16/12) and was pitched with WLP002 straight from the vile (never had a problem doing this before).

Thought I had better check on the 10 gallons of WIT I brewed after the Porter and found that it too is stuck! WTF. The WIT Started @ 1.050 (9/30/12) with WLP410 and is now stuck at 1.018 (10/21/12). It was pitched directly onto the cake of my previous batch and experienced EXPLOSIVE fermentation within a day.

We have had a couple of cold snaps around here, but my basement usually stays between 65-72 year round. Also, did the same techniques as my previous (many) batches on both.

I am completely at a loss here... Anyone have any suggestions?

Would pitching more yeast help? How about a different strain to finish it up? Ive got some WLP001 at my disposal immediately... Seriously considering it, but was wondering if anyone else has some ideas.

Did you check your hydrometer to make sure it's at 1.000? You're not using a refractometer, right?

We talking extract or AG? If your AG, you may be mashing way too high due to a faulty thermometer.

Yooper said:

Did you check your hydrometer to make sure it's at 1.000? You're not using a refractometer, right?

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Yes, put it in some water for a 1.000 right away.

Hammy71 said:

We talking extract or AG? If your AG, you may be mashing way too high due to a faulty thermometer.

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I always use multiple thermometers: One on my brew kettle for heating mash water, a digital food thermometer, and a candy/deep fry old school thermo. They all match on another within about 3-4 degrees consistently.

These are definitely not through, tasting them leaves little to no trace of alcohol and obvious sweetness still in the wort.

clblittle said:

I always use multiple thermometers: One on my brew kettle for heating mash water, a digital food thermometer, and a candy/deep fry old school thermo. They all match on another within about 3-4 degrees consistently.

These are definitely not through, tasting them leaves little to no trace of alcohol and obvious sweetness still in the wort.

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But a 4 degree difference is HUGE! If you think you're mashing at 156, and are actually at 160, the beer will be a totally different beer and finish sweet with a high FG.

If your mash temp varies by that much, that could be the cause of the problem.

The variability between thermometers, even among the same model, is surprisingly bad. Unless you fork out big bucks for a lab grade meter, there can be as much as 3-4 degrees variance. Try to use one that at least can be calibrated at 32F in ice water.and check the spec for accuracy.

It's my understanding that extract batches might finish a couple thousandths higher gravity. The 1.018 might be complete.

The 1.030 - a lot of people will disagree with me - a lot - do a little research and consider aerating it and pitching a little more yeast.

I wouldn't bottle it like that.

Well, I "shook" up the porter and see a little bit of activity this morning in the airlock. Ive got my fingers crossed that it is going to get going again. Seriously hoping it isnt just out-gassing the air I shook into it.

On the WIT, if it doesn't move in a week or so I am just going to live with it. It tastes good, so it might be better as a low alcohol session beer. Ill just be sure to keg it rather then bottle.

As far as thermometers, I hear you. Without the funds for a high end thermo, what are you all using? I always figured that by keeping track on multiple thermos, I had my bases covered and was probably hitting within a reasonable range. Might be wrong on that one.

I usually mash in low and raise the temp to my target. Target on each of these was 150, which I hit on both. So even if the thermo is off by 4 deg., 154 isn't a deal breaker as far as fermentable sugar is it? Just changes the beers taste, right?

I appreciate your help as always! Learning something new here almost everyday!

It official: Porter is back up.

Guess I need to get myself some aeration equipment. A problem solved and an excuse to get a new toy.

clblittle said:

I usually mash in low and raise the temp to my target. Target on each of these was 150, which I hit on both. So even if the thermo is off by 4 deg., 154 isn't a deal breaker as far as fermentable sugar is it? Just changes the beers taste, right?

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Lower mash temps should leave less un-fermentables. Your yeast will use up the sugars better and your beer will have less sweetness, lighter body, and better conversion of sugars present to alcohol.

If you like Porters, you should check out Orfy's - Boddington's Bitter Clone.

(It's not that bitter)

clblittle said:

It official: Porter is back up.

Guess I need to get myself some aeration equipment. A problem solved and an excuse to get a new toy.

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Aeration techniques may or may not help this particular problem, but here's an idea: if you are trying this recipe again in the near future, incorporate ONE new technique at a time. If you try making more than one improvement at a time, you probably won't know the exact culprit of your previous troubles. For all you know, you could have even had a mutant cell in your yeast.

Porters are supposed to finish on the wet side, but yeah, 1.030 is buzzkill high. Yes, aerating your chilled wort will almost always guarantee healthy yeast cell multiplicity and initial fermenting activity, especially if used in conjunction with a starter. If you opt to buy an aeration system, it would worth it to utilize an inline sanitary filter, you can usually get them from your LHBS for about $5.

Remember to never overlook any sanitizing practices. And always boil your beer stone.