Repitching onto yeast cake within 3 days

When pitching on a cake, timing is everything if you are lazy like I am. Rack the 1st beer and immediately dump the 2nd beer (higher gravity, imho) into the 1st beer's pail/carboy...imho, ymmv

 

My best advice would be to take the slurry and disperse it into three sterile mason jars so then you have three batches of yeast ready to go. That way you aren’t overpitching and you have yeast for another two batches. $$$ saver.
Also I wouldn’t secondary for dry hopping but that’s just me.

 

Mason jars is good if you have the jars and time. Dumping into the bucket after racking works as well. It's harder to save yeast after dry hopping in the primary with out washing,,,, or you
L have mason jars with yeast and hop residue, especially if you use a bunch of pellets.

 

Once after racking a beer from primary I was pressed for time (aka, lazy) and left the yeast cake (with lid sealed) to be cleaned later. Two days later when I went back there was mold growing on the krausen ring.

After racking, the entire primary will be filled with air and all the assorted microbes that go with it. If your air is really free of microscopic critters you'll be okay . . . but it's a risk I would not take. Based on my experience it's likely to be infected.

If you plan on storing in jars it's really not too difficult to go ahead and wash/rinse your yeast and eliminate as much of the trub as possible. After transferring to jars, the yeast will floc out within a day if you refrigerate. Here's a decent video on the subject:



BTW, even if you don't wash/rinse I would store the jars in the fridge. This will inhibit growth of anything you might pick up in the process.

 

I don’t wash or rinse or any of that Jazz. Take the slurry for what it is and seperate it into three jars. I do this for not dry hopped beers and it works fine. If people are so lazy they are willing to pitch on a yeast cake than why take the time to wash or rinse yeast. One batch makes 3 jars of yeast slurry. I just used the final jar of saison yeast from the first batch. Now I can either buy new yeast
or make another three jars from the next batch and I’m still only on my second generation.

Edit: I also top crop to get ale yeasts pure sample at times.

 

Well, you certainly killed at least some of them. How many would be a function of the thermal mass of the yeast cake, the starting temperature of the yeast cake, and how well dispersed/mixed in the added water was. The latter factor would make this very hard to model.

Then of course there's thermal shock to some cells that aren't killed outright.

 

Dump it. Easier not to wash it.

 

I don't know the thermal mass of the yeast cake, but it's certainly lower than water. My guess is that the 200F water probably did some significant damage.

 

Especially if there's not a lot of trub. If you see a thick layer of trub than it is probably worth at least one wash. If I do attempt a wash I'll mix in some water than dump in my bottling bucket. Let it sit 15 minutes than put in the jars. But most of the time I skip washing.

Of course there are plenty of times I forget I was planning to save my yeast like last night. D'oh!

 

The first time I tried to save yeast, I had it all washed and put in sanitized jars...then put them to store in the freezer. haha. that's how I learned not to freeze them. I tried to start them but they were goners.

Yeast is both easy and difficult in it's own ways. Earlier this year, I pitched onto a yeast cake that was sitting on it's own in a cool (68 F) room for a few days. It was in beautiful shape when it was time to ferment, but as has been mentioned, there is always a chance for contamination. There was no signs of infection. I pitched the wort. Turned out fine.
However, to that above poster, I would suggest that the mold was possibly already present somewhere in the fermenter. Of course, it's always possible that airborne contamination occurs, at any stage.

If It's not too late, I would consider it a big win that you dumped the 350ml of 200 F water onto the cake, because you killed maybe half the yeast, meaning as long as there is no infection, you are ready to pour some new wort on! The dead yeast will serve to nourish the new, budding yeast. Fresher than any available yeast "nutrient," and no overpitch.

You can still save the yeast after this batch.

 

Yeast can use parts of dead yeast cells as nutrients, which is why yeast hulls are included in some nutrient mixes. Yeast hulls, by the way, are not whole yeast cells, but I digress. Half a yeast cake's worth of dead cells is a sh*tload of decaying, autolysis prone cells. There's no way I would recommend pitching onto that.

 

IMO a better method than pitching on a yeast cake or rinsing/washing is to make your new starter around 1/3 more than what you need. Then pour off this excess and store for next brew day. Often I'll use the final runnings (free wort) and re-start what I just poured off and get somewhere around 60 - 100B cells to store. Overall this is easier to manage sanitation and almost no effort except for an extra dab of DME.

 

Or maybe he killed 90% of the yeast, there is no easy way to know

 

Pitch on the whole fucking cake...prove to me that potential 100% over-pitching is detrimental.