How much when repitching from yeast slurry

Post #1 made 8 years ago
I haven't tried it before but thought I'd give yeast washing/re-using a go. I've got a bottle of my old yeast which has been washed in the fridge, I've gotten rid of any trub and any top floating beer/water to leave me with about 200mls or so of yeast slurry.
I only do small batches of around 2.5G/10L (into fermenter) so I was wondering how much of this yeast slurry I should pitch into my next brew (OG ~ 1.050)?
I tried using the Mrmalty.com website but it suggested I only need 43 ml, that's only 3 tablespoons!

Any thoughts on the appropriate amount?

Thanks

Post #2 made 8 years ago
Chesl73, The amonut of yeast you Start with, will change the Time it takes to Ferment the Wort.

So if your Fermenting at lower temperatures, you could use 1/2 the Yeast, to help it get going Quicker.

If your looking for the yeast Flavors that occur after a thousand regeneration's, use the 3 Tablespoons.

The more yeast you use, increases the Fermentation, and make it Quicker....
Image
Just make sure you have a LOT of Head space in the fermenter.
Image
Last edited by joshua on 06 Jan 2016, 12:33, edited 1 time in total.
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Post #3 made 8 years ago
joshua wrote:
Just make sure you have a LOT of Head space in the fermenter.
Thanks joshua - I don't know why I don't just ping you directly as you answer all my questions anyway :salute:

I suppose were I was coming from was that 200ml might not be enough but from what you are saying I could even split that into two and use it for two different brews as 100ml would be more than enough - yes?

Or just throw the full 200ml and be done with it?
Last edited by chesl73 on 06 Jan 2016, 17:02, edited 1 time in total.

Post #4 made 8 years ago
chesl73, I would use the yeast for two Batches, since your doing a 10L batch.

But, if your doing a Lager style batch, a Bigger starter is better.
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Post #5 made 8 years ago
joshua wrote:Chesl73, The amonut of yeast you Start with, will change the Time it takes to Ferment the Wort.

So if your Fermenting at lower temperatures, you could use 1/2 the Yeast, to help it get going Quicker.

If your looking for the yeast Flavors that occur after a thousand regeneration's, use the 3 Tablespoons.

The more yeast you use, increases the Fermentation, and make it Quicker....
Image
Just make sure you have a LOT of Head space in the fermenter.
Image
You've lost me again Josh :). I don't understand this post at all. Good thing chesl73 does though :lol:.

The way I am reading things, Josh's saying, "if your Fermenting at lower temperatures, you could use 1/2 the Yeast, to help it get going Quicker (sic)" is incorrect but maybe it's just a few typos? But then Josh says...

"If your looking for the yeast Flavors that occur after a thousand regeneration's, use the 3 Tablespoons (sic)." I Have no idea what this means sorry :scratch:.

Here's my take on...

[center]Washing Yeasts[/center]

Some yeasts like the dry US-56 (now 05) are single strain yeasts that will not mutate very easily. I have washed this one for 18 months from memory without a problem until I lent the yeast to someone else - lol! Other yeasts are multi-strained and one of the strains will quickly take over the other when re-used.

Hold on! I've actually already written on this several times/years ago on this forum. Will leave it up to you guys to find the stuff. You'll actually find out how to wash as well!

Digging that old info up, re-posting it or linking it here and correcting it, if necessary, would actually be a great help to the site as there are hundreds of things like this, that have been answered already that need to be transferred to the new site being worked on. You'll even get some recognition for helping out!!!

:peace:
PP
Last edited by PistolPatch on 06 Jan 2016, 21:20, edited 1 time in total.
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Post #6 made 8 years ago
PP, 200 ml of yeast, is Probably 40% yeast Nutrient, and 60% live yeast.(from My experience).

A small amount of yeast(7G) will duplicate and die off as many times as needed to create 120 grams of yeast at the end of Fermentation,
So maybe there is only 400 regeneration's of yeast, each time the yeast will change a bit to adjust to the wort, and alcohol content.
The yeast you started with, is not the yeast you end up with. Very close, but not the Same.
I was assuming the 200ml, was washed well, and has had no nutrients for a while.

For a Wyeast Lab write-up on yeast see....
https://www.wyeastlab.com/com-yeast-harvest.cfm
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Post #8 made 8 years ago
My yeast in question is the US-05 one. I'm just doing a standard 'Ale' with the washed yeast.

I've seen a few posts (on the wider web) about only re-pitching yeast if you are going from a lower to higher (?) gravity beer - would you guys agree with this or doesn't matter too much?

Post #9 made 8 years ago
chesl73, if you pulled your Yeast early in the Fermentation, it will work like New yeast.
Image
If you pulled the yeast after Fermentation, it "learned" to Tolerate your Final ABV from the last Batch.
Image
In reality, Yeast is Just, Yeast, it needs to eat Sugar, Pee Alcohol, and Fart Co2.
Image
You can Re-pitch the Yeast from Batch to Batch, if is Washed and Feed.
Image
The Original Gravity will effect the Yeast very Little, But your saved Yeast WILL tolerate Higher Gravity, and Higher ABV.
Image
Last edited by joshua on 07 Jan 2016, 07:47, edited 1 time in total.
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Post #10 made 8 years ago
I've made up larger starters and saved some as Rick mentioned and I will be doing it again.
Whenever pitching yeast (new, washed ect) you need to pitch the optimum amount. There is a fairly wide range of what is optimal and the online calculators can get you in that range.
Over pitching and under pitching are just as detrimental to the beer as improper ferm temps.
Under pitching causes stress and can kill off yeast cells.
Over pitching as Josh recommended starts active fermentation(or exponential growth phase) faster but results in weak malnurished yeast cells that will end up being just as stressed.
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Post #11 made 8 years ago
I dumped cooled wort on top of the old yeast cake once and made good beer.

Now I usually reserve about 1 cup (250 ml) clean the fermenter and pitch.

Also makes good beer - with less trub at the end of fermentation.

I use hop socks for both the boil and dry hop so my trub is "cleaner".

YMMV
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Post #12 made 8 years ago
[center]ADMINISTRATION NOTE 10th January[/center]
Moving from Yeasts forum to Old Timers forum

This thread is very confusing to read. I myself am lost on several of the posts. As some more discussion continues below, I will move the thread to the old timer's forum.

Some Posts moved to Retired Forum

In the first edition of this post, I explained that I would move some off-topic posts to the retired forum after a day or so. I have done this now. The outcome of these posts was to emphasise that this is an information site unlike other brewing forums. In other words, one important aim of the site is to give new brewers safe and clear answers which we do have in most areas.
Last edited by Pat on 08 Jan 2016, 09:59, edited 1 time in total.
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Re: How much when repitching from yeast slurry

Post #13 made 8 years ago
Back to your original question...And a good post where best practice and opinions are appropriate.
chesl73 wrote:I haven't tried it before but thought I'd give yeast washing/re-using a go. I've got a bottle of my old yeast which has been washed in the fridge, I've gotten rid of any trub and any top floating beer/water to leave me with about 200mls or so of yeast slurry.
I only do small batches of around 2.5G/10L (into fermenter) so I was wondering how much of this yeast slurry I should pitch into my next brew (OG ~ 1.050)?
I tried using the Mrmalty.com website but it suggested I only need 43 ml, that's only 3 tablespoons!

Any thoughts on the appropriate amount?

Thanks
All the practices for yeast harvesting mentioned( top crop, starter harvest, bottom harvest ) are great and will all produce reusable yeast if done correctly. I this case there really isn't a best practice.
The second part of the original question there is a best practice and really no room for debate(in the beginner section ).
Pitching an appropriate amount of yeast is vital to yeast health. I use the Brewer's friend calculator http://www.brewersfriend.com/yeast-pitc ... alculator/ and it actually has a fairly wide range of how much to pitch. I have read Chris Whites Yeast book and wish I could find a reputable link to compress it into a single page.
Under pitching will overwhelm the yeast and cause stress. Over pitching will force the yeast to compete for nutrients developing weaker cells that aren't prepared to do the work.
Just because you can't see any activity during the lag phase doesn't mean nothing important is happening. The lag phase is actually quite important. The same is true after the exponential growth phase (active fermentation) things are still taking place even though there is lille evidence.
I believe Josh's advice of more yeast for warm temps and less for cooler is backwards. Cooler yeast is less active than warm.
The thought of more yeast will kick start active fermentation faster is also not totally true. You can pitch a bucket full of yeast into an under aerated and under nutrition wart and end up with a slow start. In this case properly pitched yeast could be faster.
Last edited by Lumpy5oh on 09 Jan 2016, 10:10, edited 1 time in total.
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Post #14 made 8 years ago
Primavera wrote:I dumped cooled wort on top of the old yeast cake once and made good beer.

Now I usually reserve about 1 cup (250 ml) clean the fermenter and pitch.

Also makes good beer - with less trub at the end of fermentation.

I use hop socks for both the boil and dry hop so my trub is "cleaner".

YMMV
Not sure if I peed in anyone's cornflakes with my original post - but to get back OT:

I have been been reusing yeast from batch-to-batch, reserving 250ml, cleaning and pitching with a blast of O2.
On my last batch (3rd generation WLP002) the yeast attenuated much more than on prior batches.
Beer was still good, albeit drier. Could be a result of a mutation or some wild yeasties in there.

Disclaimer - I am only sharing my experiences - not providing any solid science. YMMV
Last edited by Primavera on 09 Jan 2016, 10:23, edited 1 time in total.
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Post #15 made 8 years ago
Primavera, as I wrote above, each regeneration of the yeast, taken from the fermenter, will have Learned(Evolved) into a stronger ABV yeast.
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Just a little on each Recycle.
Image
Sam Adams(Boston brewery) has a "Ninja" yeast that tolerates over 20% ABV, developed over 12 years.
Image
Last edited by joshua on 09 Jan 2016, 11:26, edited 1 time in total.
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How much when repitching from yeast slurry

Post #16 made 8 years ago
I think yeast is often the forgotten element of brewing. Brewers make wort but yeast makes beer. The problem is that as yeast is so versatile and resilient that it will do that under a wide variety of circumstances and can be pretty forgiving to approaches that may not be 'best practice' whatever that might be.

There may be an ideal number of yeast for a given wort in terms of yeast health but there are always exceptions where stressing the yeast can result in desirable flavours.

One example would be. Hefeweizen where under pitching is done deliberately to add to the flavour.

I have used dry yeast both sprinkled and rehydrated as well as liquid yeast with or without a starter, scooped yeast out of the bottom of a fermenter, pitched wort on an entire yeast cake. A lot of these aren't great practice but all have made beer and some have made great beer.

When thinking about how much slurry to use you need to consider what the wort you are trying to ferment and what you are hoping to achieve in terms of flavour. Yeast strain, fermenting temperature and pitch rate are all important for the final flavour.

For example I have made a RIS with a OG of 1.090 and pitched it onto a full cake of a saison yeast but fermented at 18C. What I was hoping for was a yeast that could get the FG relatively low but without the yeast driven flavours saison yeasts are known for, especially at higher temperatures.

I have also pitched about 100mL of slurry into a Hefeweizen 20L at 1.045 because I was after the flavours that yeast produces under stress.

I am also well into the process of building a 3.5L starter for 15L of Pilsner. It will be pitched tomorrow or the next day at about 10C so a big pitch of healthy yeast is necessary to ensure the clean flavour associated with the style.

250mL of slurry is a reasonable pitch for most beers at 1.045 to 1.050 but there is no blanket rule.

The best thing is to think about what character you want the yeast to bring to the beer and then consider the conditions that are most likely to bring that about.

Post #17 made 8 years ago
Contrarian - thanks for the post. for some reason I have been very hesitant about how I use yeast (maybe still a newbie thing) - but your whole attitude on understanding what you are going for and how to potentially manipulate the yeast based on the wort and temperature etc. has made me feel a bit more confident in chilling out about "yeast" -
thanks,
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How much when repitching from yeast slurry

Post #18 made 8 years ago
I just used 2 or 3 different dried yeasts for ages and it was only when I started using liquid yeasts that I became more interested in getting a couple of brews out of each packet.

Like most things brewing there is an endless pit of knowledge about yeast to disappear down but you can make good beer with a fairly limited understanding of it all.

As you branch out into different styles and do a bit of reading about them your knowledge and understanding will grow but the best way to get a feel for things is to brew and taste them!

Brewing should be fun, not something where you are paralyzed by the fear of what might happen. If you have a good reasoning for what you are doing based on your current understanding then you are growing as a brewer and that's what it is all about!

Post #19 made 8 years ago
If you are making your OWN beer, and using Dry Yeast, you can save $$$$, bu re-hydrating the dry yeast, and Feeding them Some Corn Sugar/Pale extract to make a good Size batch.

Then make 40-50 Slants as Yeasty did at http://www.biabrewer.info/viewtopic.php?f=86&t=1372 and have enough yeast to brew for a year or more, and Never Care about Re-using Yeast.
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Post #20 made 8 years ago
OK - so I admit I did not even know what a yeast slant was. I do now and thats what counts (thanks) If I guessed I would have been close. Anyway - I have a couple of White Lab tubes that I did not through away, so I think I will try and create a couple slants myself as soon as I understand what the hell an agar is - haha. No seriously as you you guys say best way is to brew and taste so I will harvest next couple of brew yeasts and see where it takes me. (say what you want about the site, I think it is "F"'n awesome.
Thanks guys,
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