yeast co2 production

[Merleti]

Noticing the opposite of what I would think to be good yeast activity sometimes.
After pitching yeast with in 3 days sometimes I saw nice to no co2 production.

All at 68 deg with 40 sec. of oxygen before pitch. 3/4" pipe for co2 gas off. All dry yeast was hydrated. Thump means it is blowing bubbles out of the pipe often. 5.5-6 gal batches

White labs 004 1.5 liter starter major co2 spill out OG 1.085
Fermentis K-97 11.5grams good thump up to 1 per sec at high K. old date OG 1.051
Fermentis 05 11.5 gram no thump new date OG 1.058
Fermentis 04 23 grams no thump new date OG 1.046

Fermentis 05 with a new date I would think should thump. Fermentis 04 doubled up with a new date should thump even more. K- 97 the sloth of the group with an old date thumps.

Your thoughts.

 

[ChaosB]

Depending on the length of the blow off tube, it seems to me you could have a lot of room for gas in a 3/4 tube. I'm told that bubbling air locks and the like aren't the best indication of fermentation. Depending on your fermentation vessel, there could be more than one way for gases to escape with less than air tight seals. Which is fine, we're just trying to keep bacteria out. From the limited experience I've had with active fermentation thus far, I can see co2 production in the wort itself, there's a fizziness rising up and creating a layer of small bubbles just underneath the krausen.

And after 3 days, I've seen my fermentations slow down so if you're gauging off bubbling air lock / blow off tube, you're definitely going to see that diminish over time.

I noticed you posted the OG's but did you reach your FG's? What's causing your concern for "good yeast activity" beyond lacking visible gas production?

 

[RPh_Guy]

Length/size of the blow-off tube won't affect bubbling rate or cause any lag in gas expulsion because the headspace and running are already 100% filled with gas before generation even begins.

It's true that bubbling is a bad indication of fermentation progress. Fermenters can leak, or sometimes people don't even notice that fermentation rapidly completed. Use a hydrometer.

A sealed fermenter is important not only to keep out contaminants, but also keep out oxygen.

How did you rehydrate the dry yeast?

 

[Merleti]

Thank you for the replies.

The blow of tubes are all the same length.

I doubt it would be the fermenter leaking as the 05 acts the same way each time.

RPh Guy rehydration was done with the typical 90 degree water with the yeast sprinkled on top for 15 min. Then stirred and let sit for 5 more min. Then dropping the temp below 80 deg (takes about 10-15 min) before pitching the yeast.

All the beer ends up fermenting as expected. 05 drops the gravity the fastest and the K-97 the slowest.

I know many people say "then what are you worried about?". I'm not worried I want to know why. I find when you know why it helps you as a better brewer.

 

[mongoose33]

What kind of fermenter are you using? Is it one where the lid may or may not seal adequately? Or that you haven't completely sealed the fermenter otherwise?

The size of the tube isn't going to make any difference in terms of how much CO2 is apparent--you will produce approximately 1 volume of CO2 for every 2 gravity points. If you dropped from 1.060 to 1.010, for example, that would be 25x the volume of wort fermenting into beer, or if it is 5 gallons fermenting, it's producing approximately 125 (!) gallons of CO2.

You'd notice, in other words.

It's pretty common for home brewers using plastic buckets as fermenters to not see bubbling, because the lid hasn't sealed and the CO2 escapes the fermenter that way.

 

[Merleti]

I am using 5 gal buckets. I think it would be to much of a coincidence that I do not seal the lid all the way on all my 05 and 04 beers but get a solid seal on the k-97. I would also think when I doubled up on the 04 that that would make a difference. They all produce bubbles. The 05 bubbles slowly for 4 days where the k-97 went gang buster for 1.5 days and then barley bubbled. It's like the tortoise and the hair.

 

[mongoose33]

I am using 5 gal buckets. I think it would be to much of a coincidence that I do not seal the lid all the way on all my 05 and 04 beers but get a solid seal on the k-97. I would also think when I doubled up on the 04 that that would make a difference. They all produce bubbles. The 05 bubbles slowly for 4 days where the k-97 went gang buster for 1.5 days and then barley bubbled. It's like the tortoise and the hair.

As soon as someone says they're using buckets, and don't have bubbling, it's 100 to 1 that it's not sealed someplace, either the lid to the bucket, the stopper, or the airlock.

Coincidences happen. Unless your yeast has been baked or otherwise compromised, look for a leak, especially if you have evidence of krausen having formed.

BTW, this is not a bashing of buckets, just that they don't always seal.

 

[BrewInspector]

It's just a factor of the way each particular yeast works given what they have to consume and in in what environment they are doing it. Each is different with distinct biology

Some are fast fermenters. Others not so much. They each produce and consume products based on their individual biology. Just like flocculation. Some drop quickly others stay in suspension.

 

[Merleti]

mongoose33 They all produce bubbles.

I would think the 05 would produce the bubbles faster as it took 4 days to bring a 1.062 down to 1.014 in 4 days. The k-97 took 12 days to bring 1.051 to 1.010 and bubbled like crazy the first couple of days.

Thank you all again for your replies. I'll get back on the rails again.

 

[BrewInspector]

Sure, but then one does not necessarily have anything to do with the other. Think about some bread yeasts... They were selected for their ability to produce lots of CO2 in a dense media. They are not so good at fermenting beer though.

 

[Merleti]

I guess I should not have assumed.