Slow fermentation with wyeast 1968

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mithion

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I have a question about fermentation speed. In september, I brewed an ESB with a starting gravity around 1.055. I used the wyeast 1968 strain cause I heard it had a good flavor profile. After pitching the yeast, I noticed a long lag time. It was close to 48 hours before I started seeing airlock activity. I was concerned, but I let it go anyway. The fermentation was steady, but also quite slow considering the gravity of the beer. There still was airlock activity almost 2 weeks after pitching. Anyhow, forward 5 weeks, the beer turned out great. I attributed the slow fermentation due to not making a starter. I then tried washing the yeast and storing it to use it again.

So last week I decided to brew another English beer. I was a bit short on cash so I decided to do a standard bitter using the same yeast. This time, I made a 1 quart starter to make sure the yeast I washed the month before was viable and not too contaminated. So I pitch the yeast in the starter after letting it warm up a bit, and unsurprisingly, the I see activity within a few hours. By the next day, the starter was really foaming up nicely so I new the yeast was at least in good shape. I brewed the standard bitter and by the evening, I was ready to pitch the yeast. I gave it a good whiff to make sure I didn't detect any funky smells which would indicate obvious infection and came out clean.

So then I pitched it... and waited... and waited... Well, it took another 36 hours before I saw any airlock activity. And now that it's been over a week since I pitched, there is still airlock activity. This beer had a starting gravity around 1.044. With this gravity, and using a quart starter, thsi yeast should have been done by now. What is the matter with it?
 
I think you need to take a sample for a gravity reading. Airlock activity is good information, but you can be deceived by the CO2 slowly coming out of solution for some time after fermentation has stopped.
 
Well, there are two other signs I'm relying on to state fermentation is still going on. First off, the beer is still quite murky which means the yeast is still in suspension. This particular strain flocculates like cottage cheese when it's done doing its business. So the fact it hasn't dropped yet means it's still eating sugar. The other thing is there is still a nice half inch to inch thick foamy head on the top of it.
 
The ESB I did last month fermented around 68-70. And this latest beer is fermenting closer to 65. I figure those are within the "optimal" fermentation temperatures.
 
So any clues why the fermentation have been both slow to start and slow to complete by English yeast standards?
 
Going by the amount of time until you "see" activity is sorta pointless. Some strains take a while to "show" activity, so don't go by that basis. You might consider looking at your aeration techniques - yeast need oxygen to multiply, and after they multiply to a really good level, you'll probably start to see the krausen form. If your wort is low in oxygen, it's just going to take longer for fermentation to start.
 
Oxygen. I haven't thought about that. Maybe there just is too little of it in my wort, and the yeast can't multiply to a large population to get the job done quickly. I'll have to try something different next time.
 
Well, I just brewed an IPA few weeks ago. I was careful in aerating it by splashing it vigorously for a few minutes but even though I did that, it's still taking weeks to get a reasonable final gravity. I still have two more mason jars of the 1968 yeast but I'm wondering if I should just get rid of it. Maybe I got a bad pack of yeast or something and the yeast is just permanently messed up. I'm thinking a redoing another ESB as my next beer (the first one went down so well :tank:). I'm going to try to change my starter a bit. I've doing 24 hour starters but I'm thinking about doubling that to 48 hours to increase pitching rate. If that doesn't give me a healthier fermentation, I will get rid of the last mason jar and move on to a new pack of yeast.
 
I just used 1968 in an IPA with no starter, fementation took off within 12hr My OG was 1.070 Maybe it was a bad pack that got over heated before you got it? It made a great IPA by the way :)
 
I haven't checked the final gravity, but I have a brown goiing right now that used 1968 and with my starter it was going in a max of 24 hours and is almost finished at one week. It is a really good yeast, you just have to manage it correctly.
 
Oxygen. I haven't thought about that. Maybe there just is too little of it in my wort, and the yeast can't multiply to a large population to get the job done quickly. I'll have to try something different next time.

My experience has been the opposite: when there has been more oxygen in the wort it has lead to an increased lag-time.

And this makes sense because the yeast don't start eating sugar until they have finished with the oxygen first; so it should take longer to take off since this won't happen until the oxygen is gone.
 
My experience has been the opposite: when there has been more oxygen in the wort it has lead to an increased lag-time.

And this makes sense because the yeast don't start eating sugar until they have finished with the oxygen first; so it should take longer to take off since this won't happen until the oxygen is gone.

That's an interesting point. However, if the wort is rich in oxygen and you get good yeast multiplication, you should have a very rapid fermentation once the yeast does get to tackle the sugars. My fermentation dragged on and on anyway. I've ruled out oxygen being a problem. I did a quart starter with all three beers but maybe I needed to let it sit longer than the 24 hours I usually do. So my pitching rate may not be optimal. But someone said they got a quick fermentation from no starter so I'm leaning towards just a bad batch of yeast from start.
 
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