Brewing on bottle day, use same yeast

[BrewsterFish]

So my friend said I could brew on bottle day and pour the new wort onto the yeast in the same carboy. If I did this I would make the same beer, but I imagine there would be some flavor differences, possible off flavors, maybe risk of contamination??
I am just curious if anyone has tried this or had an idea of how it might go.

 

[Sammy86]

Numerous people on this forum do exactly what you describe...take beer off the yeast cake into a bottle bucket or keg and then put new beer on.

There may be some flavor imparted from the past beer but you shouldn't have any problems fermentation wise.

Cheers!

 

[Sadu]

Do it!!! It's awesome! Saves money, you get a high pitch rate and less cleanup.

I find that bottling is a perfect activity to occupy the time while you wait for the mash or boil. Not having to clean / sanitise the fermenter is an added bonus.

You don't have to make the same kind of beer, just something that uses the same yeast. People say that you should try to move upwards in gravity, ie brown ale -> porter -> wee heavy-> RIS not the other way around.

You will find that if you pitch the new wort on top of the old yeast it will be a huge overpitch. This isn't a big problem, but it's probably a better idea to remove 1/2 to 3/4 of the yeast/trub with a sanitised cup. You want to leave behind 2-3 cups, that will be plenty for a robust fermentation.

I plan my brew days around reusing the yeast as much as possible, it's so much easier than mucking around with starters, and cheaper than buying new yeast for each brew.

 

[flars]

You will probably have enough yeast in the fermentor for at least four new beers. Harvest the yeast and pitch part of it saving the remainder.

This is good reading.
https://www.homebrewtalk.com/showthread.php?t=579350

Not pouring the hop debris from the boil kettle into the fermentor will give you some very clean yeast to harvest.

 

[BrewsterFish]

Do it!!! It's awesome! Saves money, you get a high pitch rate and less cleanup.

I find that bottling is a perfect activity to occupy the time while you wait for the mash or boil. Not having to clean / sanitise the fermenter is an added bonus.

You don't have to make the same kind of beer, just something that uses the same yeast. People say that you should try to move upwards in gravity, ie brown ale -> porter -> wee heavy-> RIS not the other way around.

You will find that if you pitch the new wort on top of the old yeast it will be a huge overpitch. This isn't a big problem, but it's probably a better idea to remove 1/2 to 3/4 of the yeast/trub with a sanitised cup. You want to leave behind 2-3 cups, that will be plenty for a robust fermentation.

I plan my brew days around reusing the yeast as much as possible, it's so much easier than mucking around with starters, and cheaper than buying new yeast for each brew.

That is super rad. So I brewed a pale ale and may try a brown on top.

I also want to avoid messing with the yeast so if I do use all of it what are the possible outcomes?

 

[Sadu]

That is super rad. So I brewed a pale ale and may try a brown on top.

I also want to avoid messing with the yeast so if I do use all of it what are the possible outcomes?

People do pitch over the entire yeast cake and have success. I haven't tried it, and probably wouldn't. I doubt it would wreck your beer but you may get better results with less than the whole amount of yeast.

If you pitch on half the yeast that is still a huge (200%+) overpitch according to the calculators. The fermentation should take off within hours and go like a rocket until done a few days later. You will want lots of headspace in the fermenter and possibly a blowoff tube. Last beer I did a big pitch like this tasted excellent, very nice blonde ale.

If you pitch onto the whole yeast cake, you will get a very fast fermentation. I can't attest to this myself but some say that certain (good) flavours are produced during the yeast reproductive phase. If you pitch too much then the yeast don't need to reproduce to the same degree and you miss out on those flavours.

To me I think the risk of infection is very low if you carefully scrape out the yeast with a sanitised stainless utensil and transfer to a sanitised jar for storage. I would prefer to have a medium overpitch than a massive overpitch, plus a bit of backup yeast in the fridge for later.

That said, people pitch onto all the yeast and if that's the way you want to go, all good.

 

[Sadu]

I also do different batch sizes. If I want to brew a large batch or a lager I will brew a smaller sized batch first and build up the yeast cake.

eg 10 gallon batch that wants 400b yeast cells and the liquid pack only has 80b? Brew a 3 gallon session beer first, steal the yeast cake which has 800b+ cells, no starters needed.

 

[rrvbrad88]

One question-for the people that do this, do you clean your fermenter at all before adding your next batch on the old yeast? For example, do you wipe out the old krausen layer or the sides at all or is it best to just leave everything as it was in the fermenter?

 

[Yooper]

This question is really popular today and yesterday! I know I"ve posted the same thing about 3 times, but I would NOT pitch on the yeast cake.

There are several reasons why- it's certainly overpitching, it's a waste of good yeast (you have enough for like 5 batches in there- sanitize some jars and save the yeast for the next four batches), etc.

This is great reading with the "whys" that are science and real world based: https://www.homebrewtalk.com/showthread.php?t=166221

I have about 8 mason jars full of different strains of yeast in my fridge, as I buy yeast about twice per year. I make 10 gallon sized batches, and one pint of yeast is more than enough for 10 gallons. I save a ton of money this way.

Just take out a sanitized cup of the yeast cake and use that, and use a clean and sanitized fermenter. The beer will be better for it, and you'll have a ton of yeast to use for the future batches in the fridge.

 

[hercher]

If you aren't comfortable with scraping some of the yeast out (assuming you are using a fermentation vessel that allows that!), then you can leave a little beer behind after bottling, swirl it around to get the yeast back into suspension, then pull some of that yeast out. As others here have said, have some sanitized mason jars or growlers ready, and put that yeast in to save for the future.

FYI, I have gone from larger beers down to smaller or lighter beers with success. I probably wouldn't do it after making a barley wine or RIS because you've stressed that yeast out. But you can easily go from a 6% brown ale to a 4-5% session beer without a problem. There may be some scientific reason not to do it, but anecdotally I've had perfectly good results.