Re-using Yeast

[JaCk_SpArRoW]

I was given this link & thought it might be of interest to someone who is wanting to know how to re-use yeast.

http://byo.com/mrwizard/1377.html

[shane_vor]

Here's a question...I seen mention made of adding a hop pellet when culturing yeast. Why? Can someone explain this?

[General]

I'm actually doing this very thing as we speak.

I'm following instructions that I gleaned from the net, where you harvest, put in a 2L coke bottle with about 1L water with 100g malt with a bung & airlock, after 48 hours pour into 6 x 600ml coke bottles and store in the fridge for 6 - 12 months.

Apparently you can use one of the 6 coke bottles to re-harvest into the 2L bottle again, and do so 5 times, making one yeast harvest into 26 starters before mutation takes over and ruins your day.

Shane,

I transferred a pretty hefty amount of hop pellet remains with my harvest last weekend, and think it may be to make the starters more consistent with the original style, as the starter has the same ingredients as the full batch did, and can therefore reproduce the flavour.

It's a trick used by the wineries as well, they harvest the slurry from all their batches, mix 50% water, 25% glycerine, 25% slurry, and freeze. Then when they have a really successful "year", they can reproduce the flavour in future batches.

[shane_vor]

Call me a bit thick if you will, reusing or culturing yeast is about the beasties themselves. I still don't see why the addition of a hop pellet to a culture is required or even the reason behind it. Especially if the recipe used is the same in the wort. See if the culturing process is to reuse the yeast, why make up a complete mini-wort for the culture? Especially if the main wort is the same recipe?

I've read a fair bit from the Whitelabs founder about culturing yeast strains and he makes no mention of the addition of hops. Why do homebrewers do it?

I saw that question about oxygenation, just wait till I try to get my head around THAT little conundrum!

[Rubber.Piggy]

could it be as a preservative / inhibitor of undesirables??

[General]

I get you now, I don't know why people add hops, and only did it by accident myself (it came with the slurry).

The mini-wort idea I do know about though.

It encourages the yeast to produce the right types of enzimes, rather than encouraging effort to ferment one type of sugar, then shocking it with another type of sugar, and the yeast having to go to much more effort to adapt. (which can tire them out)

[chris.]

Call me a bit thick if you will, reusing or culturing yeast is about the beasties themselves. I still don't see why the addition of a hop pellet to a culture is required or even the reason behind it.!

I've never done it myself. & I also can't see a reason behind it. There is no need to do it IMO.

General, I've split many Whitelabs vial's using that method with varying success.
I've since heard, but not tried, that its best to start with a bigger starter (over 2 litres). The reason being that a small 1 litre wort stresses the yeast & inhibits reproduction. & I'd probably believe it judging on the amount of sediment in the split bottles.
I'm yet to try it, but next time I split a vial I think I'll start with a bigger starter & let it ferment out for a few days to a week. Cool it down in the fridge for a day or so, then drain off the top & split the remainder.

[MattR]

Hi Guys,

I kept some of the Saflager yeast cake when I racked a brew recently. I put it in the fridge but that isn't really much colder than the temperature it fermented at so I don't think it is going dormant.

Is it okay to put it in the freezer or will the yeast go dormant on its own when it runs out of food?

Cheers,
Matt

[drtom]

My understanding is that the bitter compounds in hops deter baterial growth, without inhibiting the yeasts. So, in short, adding hop pellets is to reduce the chance of infection.

Tom

[The Carbonator]

making one yeast harvest into 26 starters before mutation takes over and ruins your day.

I keep hearing about htis mutation of yeast, and how its a bad thing. Has anyone ever experienced yeast mutation, and what are the effects?


( Sorry about the hijack )

[General]

No problems Carb, mutation occurs when the yeast strain is split too many times, it's effect is that the yeast is no longer a "beer" yeast, so it isn't an ale or lager yeast anymore.

The side effects are different compounds are produced rather than the "good" ones.

It still converts sugar to alcohol, and CO2, but it makes fruitier flavours as well, which we technically are not looking for.

If you're not competition brewing or letting an expert drink it, who would notice.

Take a look at How to brew (palmer's book) it explains it in much more technical terms than I do.

DrTom has reminded me that hops were originally added to beer not for lavour aroma or bitternes, but as a pereservative, so it only stands to reason that they would inhibit bacterial growth.

[Aussie Claret]

Hi,
I have a question, when harvesting yeast there are many references to not harvesting dried yeast strains, does anyone know why?

Thanks
AC

[rejected]

Not sure for certain but this is my understanding.

As far as I know the dried yeast will contain more bacteria in parts per million than a liquid strain and it's likely to be more prone to mutate. It has something to do with not being able to control the levels in the drying process.

It is cheap enough to buy dry yeast and personally I would rather buy a new packet than harvest. Harvesting will increase the risk of contamination. If sanitation proceedures are very good then the problem may only be minimal.

I do harvest liquid yeast strains but only once or twice. It is safer to make a large starter and split that.

[kurtz]

Dry vs Liquid AND Harvesting
Dry yeast has been around for a long time and the companies that produce it do so under strict quality control. If your dry yeast is of a known strain (SO4/US56/3478/Nottingham etc etc etc) and is within it's use by date and is in a factory sealed pack then it should be every bit as good as a liquid yeast that is within its use by date refrigerated and such.
The advantage taht Wyeast/Whitelabs have is taht they have heaps of variety, which is no so bad when you a lab who cultures up only a few trillion cells aday. The dry guys though need trillion times and more cells to make production run efficient.
Yeast is yeast, its a single celled fungus, whether it comes to you dried or liquid is just a packaging issue.
You can do all sorts of things, you can top crop an ale yeast, you just harvest the sludge trub and all, you can wash it you can do whatever..best (but we not live in a perfect world) is to package harvest re-use on the same day !!

K

[MattR]

You can do all sorts of things, you can top crop an ale yeast, you just harvest the sludge trub and all, you can wash it you can do whatever..best (but we not live in a perfect world) is to package harvest re-use on the same day !!

So if I harvest the sludge after racking I can pitch it into a fresh wort with in a day or so?

Cheers,
Matt

[kurtz]

So if I harvest the sludge after racking I can pitch it into a fresh wort with in a day or so?

So long as you pay attention to hygiene no worries, some people wash their yeast which is better but not compulsory.
Just be careful that you harvest from the initial fermentation, if you rack your beers and then harvest from that you will over a few generations be selecting late flocculating yeast, which will cause you problems.

K

[Oliver]

... you harvest, put in a 2L coke bottle with about 1L water with 100g malt with a bung & airlock, after 48 hours pour into 6 x 600ml coke bottles and store in the fridge for 6 - 12 months.

Apparently you can use one of the 6 coke bottles to re-harvest into the 2L bottle again, and do so 5 times, making one yeast harvest into 26 starters before mutation takes over and ruins your day.

Or if you made six bottles from each bottle for five generations you could make yourself 7776 bottles of yeast

You'd never have to buy yeast again!

Cheers,

Oliver