Recurring stuck fermentations

[STL_Lucas]

So my last 4 batches have all stalled fermenting at about 1.025. The first was an Irish stout extract kit with a wyeast Irish stout yeast. Second was a cream ale extract kit, third an all grain pale ale, and fourth a nut brown extract kit all 3 with dry safale US-05.

The stout was fermented in a swamp cooler and used a yeast starter. I thought it was a combination of too low of ferm temp and un-fermentable dark extract.

The other three were all put into a chest freezer and set between 65-70. I paid extra close attention to the fourth batch and made sure it stayed at 70.

All 4 brews taste great and are very drinkable I'm just wondering if anyone has any thoughts on why I keep having this problem. Is it the choice of yeast? Should I rehydrate or make a starter? Any thoughts would be appreciated!

 

[jalmeida]

Maybe you are not aerating adequately. The easiest aeration is to free fall it into the fermentor. Make sure that it makes a good foam as it falls. I use buckets and free fall with the bucket at an angle. Just don't do this in a dusty dirty place.


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[Travestian]

You should always re-hydrate dry yeast no matter what the package says. That could be part of the issue with the US-05 batches. Liquid yeasts should have starters made for them in most cases. You didn't mention the OG on any of the batches though. If you're pitching 1 yeast pack into bigger than about 1.050 (especially with the liquid yeast) then you aren't pitching enough yeast which could also be the culprit.

It's also possible that another issue like jalmeida said is that you aren't aerating enough before pitching the yeast.

 

[Dave_K]

Have you checked the calibration of your hydrometer? Could be that it's not stalled at all, and actually finished.
You said they all tasted great, were they on the sweet side?
Are you bottle conditioning or force carbing in a keg? If it's still bottle conditioning without issue there's no reason to think it was a stalled fermentation

 

[STL_Lucas]

So aerating could be the issue. The first three were all bottle conditioned and were all an OG of about 1.052. The stout carbed up fine and was a little on the sweet side but not overwhelming. The 2nd and 3rd batches were also bottle conditioned and they did not carb up enough. They did a little bit but we're definitely under carbonated. The 4th batch was kegged and force carbed. I usually siphon out of my kettle through a sanitized strainer. What are the most sanitary ways to aerate properly?

 

[The_Bishop]

Check your hydrometer in RO or distilled water. It might not be accurate. Just bought a new one that was 4 points off, right out of the box.

 

[Hammy71]

Maybe you are not aerating adequately. The easiest aeration is to free fall it into the fermenter. Make sure that it makes a good foam as it falls. I use buckets and free fall with the bucket at an angle. Just don't do this in a dusty dirty place.


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This: In my experience if you think you have aerated your wort enough, you should do the process a second time because you probably didn't. Especially with stouts and dark beers. It just seems they need a lot more aeration to hit that FG you want. Rehydrating the yeast has little or no impact in my opinion. If you had a normal fermentation, then the yeast are doing what they can do with what they got. Dumping in the fermenter, shaking the bejezus out of the fermenter, fancy expensive oxygen tank, whatever you can do. I use carboys to ferment and I go low tech. Works great. It's a wine degasser tool. Been using it for going on 5 years and (knock on wood), no stuck fermentations anymore.

 

[STL_Lucas]

Thanks for the input guys. I think I'm going to invest in one of those wine degasers and give that a shot.

 

[Pkrd]

You don't have to aerate dry yeast.
http://www.fermentis.com/brewing/industrial-brewing/faq/

 

[jalmeida]

You don't have to aerate dry yeast.
http://www.fermentis.com/brewing/industrial-brewing/faq/

That link says they recommend aerating. I agree that you don't have to either. But you also don't have to have a beer hit target FG either.



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[BigFloyd]

It doesn't hurt to aerate some when using dry yeast, but it's not as critical as with liquid due to the sterols packaged with dry. Rehydrate dry yeast. Don't make a starter with it (especially w/o rehydrating first) as it's easier and roughly the same cost to pitch multiple packs for higher gravity batches.

As mentioned, I'd certainly check the hydrometer. Both of mine are off .002, but in opposite directions, and are marked accordingly.

 

[g-star]

You're not checking gravity post-fermentation with a refractometer, right?


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[STL_Lucas]

Yes I am using a refractometer. Is that bad?


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[whoaru99]

Yes. Alcohol screws up the reading. There are allegedly some conversion factors that can help but I don't know what they are.

 

[whoaru99]

According to a website that claims to have built in this correction factor, a beer starting at 1.050 and ending at 1.025 by refractometer reading is approximately 5.5%.

Whereas, by the standard calc that same reading would give only ~3.3%

By standard calc your FG would be about 1.008 to get ~5.5% from a 1.050 beer.

Assuming that website correction is close, you can see it's quite a difference.

 

[STL_Lucas]

We'll that would mean my beer is fully fermented in all 4 cases. What website are you using? That is good news, now I just don't know why the 2nd and 3rd batches didn't carb up properly.


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[Hammy71]

You're not checking gravity post-fermentation with a refractometer, right?


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Awesome question. Refractometer for OG, and Hydrometer for FG. Good catch Sir. :rockin: Edit: (I assumed the Sir part...if I''m wrong, no offense intended)

 

[STL_Lucas]

Great catch! I just plugged this all in beer smith and brewers friend and it indeed looks like I'm at about 5.5%! That is awesome news. I had no idea refractometers needed that adjustment.


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[kombat]

You don't have to aerate dry yeast.

I know what the FAQ says, and I even used to espouse that position myself, but the one batch where I actually put the theory to the test and didn't aerate at all, I ended up with a horribly banana-y pale ale. I know it's just anecdotal evidence, but now I aerate every batch, regardless of whether I'm using liquid or dry yeast.

 

[whoaru99]

What website are you using?

A few came up. I just happened to click on this one: http://www.petedrinks.com/refractometer-abv-calculator/

 

[BigFloyd]

To see for myself what the difference is between an FG checked both ways, I got simultaneous readings of a 1.035 with the refractometer and 1.017 hydrometer.

 

[mufflerbearing]

Great catch! I just plugged this all in beer smith and brewers friend and it indeed looks like I'm at about 5.5%! That is awesome news. I had no idea refractometers needed that adjustment.


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I was reading my FG with my new refractometer and it was stuck. @ 1.029. Saw this and tested with a hydro 1.013. Problem solved!!! Thanks for that!


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[jalmeida]

I was reading my FG with my new refractometer and it was stuck. @ 1.029. Saw this and tested with a hydro 1.013. Problem solved!!! Thanks for that!


Sent from my iPhone using Home Brew and I don't care for the new format so much.

On this subject, I purchased a Brix refractometer initially hoping to avoid having to drain so much beer to take readings. I felt pretty silly to find this is almost useless with alcohol. I just didn't like the wasteful amount needed to fill the vial. But now I taste a little, and if it tastes sweet I wait longer to rack. If it tastes okay then I take a hydrometer reading. Live and learn.



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[peterj]

On this subject, I purchased a Brix refractometer initially hoping to avoid having to drain so much beer to take readings. I felt pretty silly to find this is almost useless with alcohol. I just didn't like the wasteful amount needed to fill the vial. But now I taste a little, and if it tastes sweet I wait longer to rack. If it tastes okay then I take a hydrometer reading. Live and learn.



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You can still use the refractometer with one of the conversion calculators online. I don't think it's 100% accurate, but it will be pretty close. And you can compare 2 successive refractometer readings without even converting them just to see if the FG is changing at all. It's definitely more accurate than your tounge! Haha.

 

[pdxal]

I have tested the Sean Terrill refractometer conversion calculation more than a dozen times vs. hydrometer and it has been consistently within 1 point of the hydrometer.
+1 to what Peterj said, too.