BeerBorg

I brewed a 2.5 gallon batch of 100 Years War IPA on Sunday, and I used this yeast:

http://mangrovejacks.com/collections/cr ... oming-soon

I've used Mangrove Jack's before, although I can't remember if I used this particular strain. I think it's likely, though. Never had a problem, at any rate.

But this batch seems to be taking its time. It just seems lazy. Not that I'm worried, because it's krausening, and the airlock is bubbling; just not as vigorous as I've come to expect most of my fermentations.

I didn't rehydrate; just pitched it directly on top of the wort and shook it up a bit. I didn't directly aerate before pitching, because I continuously stir the wort while I'm cooling it in a cold water bath, and it gets pretty foamy anyway. I figure that aerates it plenty. Temperature has always been in this yeast's Happy Zone. So I dunno. As I said, I'm not worried, or anything. I'm just making the observation. Overall I've liked the results of this company's yeast when I've used it. But this particular batch just seems sluggish.

Oxygen in the wort is a major thing. I saw a huge difference in the lag time and the vigor of all of my fermentations once I started carrying my wort down stairs in two buckets and dumping them into the fermenter. And this is after pouring the wort into them through a strainer which areates it. The only way you could possibly get more oxygen into your wort than this (if it is even possible as there is a saturation point) would to be to use some kind of O2 infusion system. The downside is I pitch my yeast on top of about 4 inches of foam. So I usually sprinkle it in after dumping the first bucket, then kind of work it into the wort as I dump my second bucket in.

I have a pack of that I plan on using in one of my summer brews. I've read lots of good things about it but have so much harvested use I don't want to go bad to use first.
I don't think you can over oxygenate the wort. Like you Dave, I stir almost the whole time I'm cooling, I transfer threw a strainer, move from one bucket to the next AND use an aeration system. While I can't say I see the activity all that much faster, I can say that the activity is very active and I'm now hitting my FG's when I was having trouble previously.

Also, I googled this yeast and did find a number of posts from people who say it had a slow start.

I have always been under the impression that the yeast in the presents of 02 in wert were in reproduction mode and when in that mode do not produce c02 thus they do not make as much foam or alcohol until the 02 in the wert has been used up. If this is true it would make since that there would be different lag times caused by amounts of 02 in wert. Now there has to be other factors as well that come into play, type of yeast, wert temp, yeast count, water make up (IE) minerals, P H, and then there is the mash and type of grains used and so on. with this many different variables who's to say.
So I pose the question, dose the amount of 02 in the wert affect the lag time in visible sings of fermentation. I would think that high 02 levels and low yeast cell count would cause longer lag times while high yeast count with low 02 would on the flip side, makes for shorter lag times. all in all the lag time alone dose not give an accurate picture of how the fermentation is going or even if it is healthy, under pitched or over pitched. variables variables, so many variables.

@Woody/all.

Yes Woody you are correct - but it's scenario specific.

If you oxygenate your wort AND have a low cell count AND your wort also contains enough other nutrients to promote cell growth that can take advantage of the extra amount of introduced oxygen, then yes, you will increase lag time, because the lag time is the growth phase and you have a long growth phase in this scenario.

It is not true that underpitching will not ferment your beer fully, it can - it may even ferment it to a higher attenuation level - IF you have enough O2 and other nutrients to really promote a long growth phase. Because the yeast are making a huge number of hungry daughter cells.

That said, using your wort as a what amounts to a giant oxygenated starter is not recommended. The extended growth phase will affect the flavor profile.

Now if your pitching a large number of cells, either a healthy starter or using dry yeast, the growth phase will happen more quickly then an underpitched batch as it's an exponential growth process, and you are starting from a big number. Especially with modern dry yeast as it's nutrient dense in of itself due to how it is manufactured. So lag time may not seem longer, and may even be shorter if the oxygen and nutrients are making the yeast happy/not stressed/making good healthy cells quickly.

It's a balancing act to some extent - if you really over oxygenate your wort and your wort, IE using a pure oxygen system run a bit too long and the wort is nutrient dense, you could extend the growth phase regardless.

If your wort is under oxygenated or nutrient poor, then the growth phase will stop as soon as the yeast run out of one or the other, and active fermentation will start even though the cell count is lower. So you could see fermentation start up fast in this scenario too, although it may not be a healthy fermentation and may under attenuate if the cell count achieved isn't high enough.

I hope that makes sense?

I learn something new from this BORG every single day. Those who take the time and effort to enlighten us is so fricking appreciated at least by me. The knowledge of those responders is overwhelming. I will now try to use this information in my next batches as I know I don't oxygenate quite enough and my lag time, well, lags.

Mashani and to the others. I tip Dave's hat to y'all as well as my duncecap.

Salud

I wasn't really worried, just kind of "hmmm...it seems a little slow". It's going quite nicely now. Full, healthy krausen, and the airlock is bubbling about every five seconds regularly. Maybe this strain just takes a little longer to get going. Or maybe it's because, even though I was stirring throughout the cooling process, and aerating it quite well, I racked to the carboy with an auto-siphon, which is the first time I've done that with a 2.5 gallon batch.

No matter. It'll be beer.

yeast can be so frustrating. ive got 2 batches from brew demon sitting side by side...started about 4 hrs apart. same environment. same process... same variety us05 yeast.
batch one took off like a rocket. . . solid blanket of white krausen. this was the pitched dry onto wort batch. second batch was rehyrdrated and is barely making any krausen. rather it is making tiny bubbles with tiny pockets of weak foam krausen here and there. think i'll stop rehydrating. anyway, going on week 2 and the wort is getting really clear on both so it must be ok. Monday i'll check the grav and if it's around 1.01 all is well.

I tried rehydrating a few times. I never noticed any difference in performance or finished product so I don't think it is worth the extra work. One thing I will say about rehydrating though is, there is no one size fits all temperature to rehydrate yeast. It is important to see what the manufacturer recommends for rehydrating temperature. From what I read rehydrating at the wrong temperature does more harm than good.

Depending on the manufacturer and/or the strain, I've noticed that a lot of the instructions on the packet say to sprinkle directly on the wort. So I do. If there are rehydrating instructions, I follow them and rehydrate at the recommended temperature.

The way I figure it, if the manufacturer takes the trouble to print instructions, I should jolly well follow them, no?