Repitch???

[travispj123]

Here are the specifics:

2.5 gallon BIAB
Multi-Grain Red
4.5 lb 2-row
6 oz Cara Munich II
2 oz caramel wheat
2 oz chocolate rye

mash 154 deg 60 min mashout 170deg for 8 min

.5 oz Williamette 60min
.33 oz Williamette 30 min
.12 oz williamette 0 min

Measured gravity at 65 deg - 1.054
Wyeast 1099 Pitched at 65 degrees (no starter) Smack Pack never inflated

I aerated wort before pitching, I have maintained 68-70 deg for two weeks. While checking temp for the first 2 days, saw no activity(not worried). Day 3 I had a very, very thin krausen so figured I was good to go. Day 14 I check gravity - 1.038.

Question - Repitch or bottle?

 

[hercher]

It would appear to me that you underpitched. I would repitch.

 

[Nateo]

Even an old smack pack should have enough yeast to multiply to a large enough quantity to finish fermentation. If that didn't happen, I would blame the brewer, not the yeast.

Dramatically underpitching should result in more daughter cells, so once fermentation started, it would've finished with a lower-than-expected gravity.

You could add more yeast, but that doesn't address what exactly happened in your wort that prevented the yeast from thriving in the first place. I would try rousing first. Try to blow off as much CO2 as you can. See if that helps.

 

[travispj123]

Thanks for the reply, Hercher. This is only my 8th brew, but I've never had to repitch. I assume I need to make a starter due to the length of time it has been sitting as well as the evidence of slight fermentation, right? Or can I just drop a packet of Safale 05 in?

 

[travispj123]

Nateo, thanks for the tip, I'll try to see if I can get some O2 going. I assuming, since there has been some fermentation you aren't talking about a vigorous rousing, right?

Also, since I'm <10 brews in and need all the insight I can get, help me out with some suggestions on the brewer error.

This was my first liquid yeast and followed my procedures for my dry yeast brews to a "T", those brews fermented like rock stars. I didn't use a starter since I'm at such a low brew volume(probably not a good assumption). The smack pack stayed in the fridge all the way up to day of "smacking". I let it warm up to room temp before "smacking".

What are some other things I can look for to see why the yeast didn't thrive?
Thanks again for any and all suggestions!

 

[jbsg02]

Yikes, did you happen to see the date stamped on the yeast? Did you aerate the wort well?

 

[NordeastBrewer77]

Even an old smack pack should have enough yeast to multiply to a large enough quantity to finish fermentation. If that didn't happen, I would blame the brewer, not the yeast.

Dramatically underpitching should result in more daughter cells, so once fermentation started, it would've finished with a lower-than-expected gravity.

You could add more yeast, but that doesn't address what exactly happened in your wort that prevented the yeast from thriving in the first place. I would try rousing first. Try to blow off as much CO2 as you can. See if that helps.

i agree. underpitching won't result in a high FG, many other things, but not a high FG. usually a high FG is the result of too high a mash temp, under aeration, or both. your mash temp was fine, how was your aeration? since you under pitched, proper aeration would be crucial to help the yeast multiply to the proper concentration. if they didn't have enough o2 at the beginning, the beer could take an abnormally long time to reach FG.
in your case, rousing and warming the yeast is an easy way to get them going again. if that doesn't work, a repitch wouldn't hurt.

 

[travispj123]

jbsg02, when the pack didn't inflate I checked the date and it was Oct 2011. I thought that was recent enough??? I use a sanitized whisk to aerate the wort, stirring vigorously for a couple of minutes before pitching. This has worked on all of my other batches(dry yeast), so maybe I didn't aerate enough for the liquid yeast. Next time I'll whisk and shake the @*ll out of it.

 

[Nateo]

I wouldn't add O2 or try to aerate at this point. Your yeast is past the point of needing oxygen, and if you do add dry yeast later, the dry yeast won't need oxygen either.

When I rouse, I swirl the carboy/bucket/whatever around and around. This will mix up the yeast with the wort, and also blow off CO2. I'm just trying to mix up the yeast, and get rid of CO2, not introduce more air into the solution.

CO2 in water makes carbonic acid. I find the carbonate system really interesting. If you're into science, check it out:
http://research.nmsu.edu/molbio/bioinfo/tutorials/env-engr/carbonate/carbonate.html

So as you're blowing off the CO2 from the wort, you're helping keep the pH in the proper range, but you're also blowing off undesirable flavor compounds the yeast are making.

Wort starts out at an ideal pH for yeast (4-6 is great), but that pH can drop dramatically in the first few days of fermentation. Wort also starts out with great nutrition for yeast, so nutrition probably isn't an issue.

I would bet that most stuck fermentations are the result of how fermentation is handled. Pitching a lot of yeast helps mitigate other flaws in handling. It's like winning a battle with sheer numbers and brute force, vs smaller units using superior strategy. You can win either way, but there are some benefits to using smaller numbers more effectively.

 

[travispj123]

i agree. underpitching won't result in a high FG, many other things, but not a high FG. usually a high FG is the result of too high a mash temp, under aeration, or both. your mash temp was fine, how was your aeration? since you under pitched, proper aeration would be crucial to help the yeast multiply to the proper concentration. if they didn't have enough o2 at the beginning, the beer could take an abnormally long time to reach FG.
in your case, rousing and warming the yeast is an easy way to get them going again. if that doesn't work, a repitch wouldn't hurt.

I'm leaning to under aeration, since I used the same aeration method I used for my dry yeast batches(probably not enough for the non-starter liquid yeast)

Should I worry how vigorous my "rousing" needs to be? Can I shake the *&ll out of it or should I just be gently swishing my wort around in the fermentor?

Thanks for the feedback!

 

[jbsg02]

If you did that for 2 minutes, you probably aerated as well as you could. A video from wyeast says vigorous sloshing for 45 seconds can add 8ppm oxygen, which is about the max you can get from air. With a 5 month old pack of yeast, I would be surprised if more than 20% of those cells were viable. At that rate, even for a 2.5 gallon batch, you would have needed a starter.

Give it a taste, I would think if it still tastes like sweet wort you could repitch and you might save it.

 

[travispj123]

I wouldn't add O2 or try to aerate at this point. Your yeast is past the point of needing oxygen, and if you do add dry yeast later, the dry yeast won't need oxygen either.

When I rouse, I swirl the carboy/bucket/whatever around and around. This will mix up the yeast with the wort, and also blow off CO2. I'm just trying to mix up the yeast, and get rid of CO2, not introduce more air into the solution.

CO2 in water makes carbonic acid. I find the carbonate system really interesting. If you're into science, check it out:
http://research.nmsu.edu/molbio/bioinfo/tutorials/env-engr/carbonate/carbonate.html

So as you're blowing off the CO2 from the wort, you're helping keep the pH in the proper range, but you're also blowing off undesirable flavor compounds the yeast are making.

Wort starts out at an ideal pH for yeast (4-6 is great), but that pH can drop dramatically in the first few days of fermentation. Wort also starts out with great nutrition for yeast, so nutrition probably isn't an issue.

I would bet that most stuck fermentations are the result of how fermentation is handled. Pitching a lot of yeast helps mitigate other flaws in handling. It's like winning a battle with sheer numbers and brute force, vs smaller units using superior strategy. You can win either way, but there are some benefits to using smaller numbers more effectively.

Nateo, great info! That's exactly what I needed. I'm going to take yours and Nordeastbrewer's advice and swirl my wort and see what happens. If nothing, I'll drop my SA05 in. I'll post results. Thanks!