Longevity of the yeast cake?

So I just bottled my very first brew (hurrah!). The hydrometer sample I took tasted really good, as far as non-carbonated, room temp beers go. The OG was off (1.030 as opposed to 1.020), but I think that's because I added lactose, malto, and the priming sugar before taking the sample :cross:. Either that or I just took a retarded reading, but the beer smelled, looked, and tasted fine, so I'm going to go with benefit of the doubt on this one.

In any case, there was a very healthy yeast cake at the bottom after we siphoned the beer. With a sterilized implement, I took a nice sample and blopped it into a 1 liter prepared starter w/ DME and Wyeast nutrient. I had the brew in the primary for a shade over 4 weeks: do you think that yeast was still alive?

only one way to telll....do another starter and step up. if it grows your good.

Yeah, I heard that. I quite literally just pitched this one about two hours ago, so I'm not expecting anything dramatic at this point. When I pitched this originally from the activator, it took about 8ish hours to show airlock activity so I suppose I'll use that as my benchmark. If the yeast is still kicking, it probably needs time to get itself rolling. But my S-style air lock is showing pressure...

...whatev. We'll see what's up tomorrow. I need to head to the LHBS 2morrow eve for a few odds and ends, so if this starter isn't showing some obvious activity by then, I'll just pick up a fresh activator and go from there.

Man, it's really hard to tell with this one. I'm not seeing any vigorous activity, but by the same token I am seeing an occasional bubble rise up through the wort, and there's pressure in the lock. I'm gonna have to make a call on it in a couple hours...

This yeast is in lag phase - it will be a long lag followed by an EXPLOSION of activity because of the number of cells that you have.

I would suggest taking the suspended yeast fluid when it takes off and pouring it into another slightly bigger starter so that you can have lots of fresh new yeast rather than a bunch of autolysed yeast ( dead yeast bodies) that are in the original cake (they can give off flavours.)

I just brewed a batch of pale ale wort that I pitched on a yeast cake. It took off with a bang. This is the first time that I've done this and have read that it has it's upsides and downsides. The good is that it is a nice starter, and you don't have to worry as much about contamination because you aren't handling the yeast. However the downside is that I believe you are technically overpitching. I thought I'd give it a try though. I may try yeast washing next which I saw in the very informative sticky.

Throckmorton: I didn't pitch onto the cake. I got a (sterilized) sampling spoon and added about two tablespoons of the cake to a prepared starter. So I'm making a starter from the cake.

In any case, I was about to give up on it, but I'm now seeing a steady effervescence. It's not anything insane, but it kinda looks like a glass of beer that has been poured and sitting for a few minutes. A gentle flow of very small bubbles has formed, and a tiny (2-3mm) "head." I suppose I can assume at this point that it's "alive," hopefully with the Whitbread yeasties I'm looking for (and not some ungodly funk).

How would you suggest doing the transfer? Decant off the top stuff and keep the cake that's forming at the bottom -- or just the opposite, save the cake and get rid of the top liquid?

Hey Pelikan,

I realized you made a starter from the yeast cake. Just giving you another option in the future. There is tons of stuff on starters. From what I have read, you want to let the starter go until the activity dies down (around to days), toss the starter in the fridge to cold crash, pour off most of the top, then pitch the slurry at the bottom. You definately want the cake/slurry at the bottom.

Now I state the above without having done it yet. I'm planning on buiding a stir plate based off information on this site to up the yeast count from a vile of White Labs. It will also be useful when I attempt yeast washing in the future. A stir plate will keep the yeast in suspension and provide O2 which will help build their numbers.. If you search on stir plate, you'll find plenty of good info.

Maybe some more experienced members will have something additional to add.

If you do not wash your yeast you should be aware that half of the slurry that you are scooping is trub from the prior beer. This has the potential to be some nasty stuff depending on how much filtering of the wort you did prior to pitching in the fermenter. There will be sedimented proteins and other unfermented solids from the beer as well as the dead yeast that someone else mentioned. Although the dead yeast is not so much of a problem because in small quantities it can even serve as a yeast nutrient.

Also, you are definitely seeing the proper level of activity. The first couple times I did a starter I was worried about the lack of visible activity. It is different from a standard fermentation and is not nearly as violent. Also, in a starter you would be better served by a foam stopper or loosely wrapped foil than by an airlock. Oxygen is good for the yeast at this stage (replication). Part of the reason for agitation is to keep the starter wort oxygenated.

dontman said:

There will be sedimented proteins and other unfermented solids from the beer as well as the dead yeast that someone else mentioned.

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I hear what you're saying, but is there really enough nasty stuff in an approximate tablespoon of trub to cause anything approaching worrisome? And won't most or all of that garbage just settle right out again? I've read about a lot of guys pitching wort right onto a yeast/trub cake, which has exponentially more crud in it than what I'm dealing with.

Next time, save the trouble on a starter and just harvest some slurry. If you carefully harvest the tan slime - not the trub - you'll get good yeast. That'll keep a couple of weeks in the fridge.

Here's a good reference page from Wyeast. It'll save you the hassle of rebuilding your yeast with a starter.

Bob

Pelikan said:

I hear what you're saying, but is there really enough nasty stuff in an approximate tablespoon of trub to cause anything approaching worrisome? And won't most or all of that garbage just settle right out again? I've read about a lot of guys pitching wort right onto a yeast/trub cake, which has exponentially more crud in it than what I'm dealing with.

Click to expand...

when you put it like I guess I have to agree. On the other hand what you can do is pour about a quart and a half of clean water on top of the cake, swirl to mix, wait 20 mins and pour all but the last 20-25% into another jar. Repeat, and you have rinsed yeast where you have left the bad behind AND you plenty of clean slurry where you have no need to do a starter. (According to Mr. Malty)

BobNQ3X said:

Next time, save the trouble on a starter and just harvest some slurry. If you carefully harvest the tan slime - not the trub - you'll get good yeast. That'll keep a couple of weeks in the fridge.
Bob

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I do believe that what I harvested was primarily that tannish slime. I kind of grazed the top after skimming it as you suggested in the thread where I was asking about this process a few weeks back. I really, really appreciate that info, as it's what steered me in this direction, and ultimately saved me about $20 or so in yeast purchases (and that's just in the short-term).

There is a little bit of sediment at the bottom of my flask -- what appears to be some tiny (tiny) chunks of grain -- but, again, nothing I'm losing sleep over given the relatively small volume that's going to be a part of the fermenting wort. And given that it was found in the cake, after all beer had been siphoned off, I can probably assume it will settle right out again.

Good on yer! Harvesting is much easier in a conical, but it can be done from a flat-bottomed fermenter just as easily. It's just the layers are thinner; you have to exercise more care.

Bob