Some advice for re-using yeast

[BeerCheez]

I am about to re-use some yeast which I saved from a batch of beer I recently made. (I simply collected 2 Tbsp off the bottom and have kept it in a plastic container in the fridge- its about 2 weeks old) I was going to start it the same way you do when it is bought new (its a liquid Wyeast) which means making up a litre of wort and letting it multiply for two days before pitching. Does anyone have advice about this?

Cheers, BeerCheez

[flytact]

I'd give it a shot. Just give the starter a little taste before pitching to make sure there are no infections.

[BeerCheez]

Top tip! Wouldn't have thought of that, Cheers flytact!

[hoppingMad]

Thats a good idea. How much wort to use for the starter is the thing you want to know. Firstly, two weeks since saving your yeast is fine, it should still be reasonably healthy. The volume of your starter wort is the key to knowing how much viable yeast you will eventually have to pitch, although the amount you saved ( 2 tablespoons ) plays a part as well.
If your next batch is 26 litres of ale, then you want 1-2 litres of wort at 1.035-1.040 for your starter and you will be fine. As flytact says, taste it before pitching and remember it wont taste like beer, when tasting starter wort you're checking there's no infection taste first of all, and secondly you're looking for no sweetness indicating that the wort has fully fermented and yeast population is at the max for that starter, thats all. Other than that it tastes like cr*p.

For lagers, double your starter wort volume. Starting gravity of the new batch your doing plays a role too in deciding the starter wort volume. i.e. a big lager such as a Bock for instance, would require a huge starter.

[BeerCheez]

Thank you hoppingMad, I've just started it tonight in 1 Litre of wort so hopefully this will be enough for a 5 gallon batch of beer. How long will a yeast keep if refrigerated? A microbiologist friend said to keep a little of the beer over the yeast sludge and he thought it would last about a month, has this been your experience?

Cheers, BeerCheez

[hoppingMad]

This is opinion only...... I think your friend is probably correct. However some cells will remain capable of multiplying for well past a month in the fridge. I have kept a tablespoonful of Czech Pils Wyeast in the fridge for 6 months then stepped it up with a litre, then two litres, then another two litres, chilled, decanted and pitched into my 26 litre Czech Pils and everything progressed perfectly with a great final result.

The answer is, what you do with that saved yeast and how you treat it before pitching it into your next beer. Some more knowledgable than I, may say that you run the risk of mutation during longer refrigeration ?????? I have no idea how that works, I'll leave that to them.

I am finding that with these Wyeasts, its a great idea to have ( within reason) a brewing schedule planned a little in advance that permits the best use of slurry as soon as possible for subsequent batches, and therby reducing the need to refrigerate so often and for long periods. i.e a pilsener followd by a Bock or a mild followed by a bitter or ESB. That kind of thing.

[Darrinfella]

Excellent. Thank you for this topic!
My wife was given a heap of lemons, which we juiced, and now we have roughly 8 litres of lemon juice in the freezer Obvoiusly there's lots of hard lemonade in my near future!
I was thinking of brewing a ginger beer (or possibly apple cider) from a can kit and keeping a litre or so after bottling, along with plenty of the bottom sludge. I've read there can be issues with the acidity of the lemon juice and getting fermentation started, so I figured a good litre or so of trub (is that the term?) should get it going, and if I use ginger beer it'll give that slight flavour edge to the finished lemonade. I've found several recipes all calling for similar quantities of lemon juice, sugar etc, so I'm reasonably comfortable with the rest of the ingredients, it's just the yeast.
I've read that bread type yeast gives a 'doughy' flavour (who would have thought....) so I'm going to assume the same is true of beer type yeasts, and beery hard lemonade doesn't sound too appealing.
My yeasty sludge will spend the night in the fridge, as I don't like the fermenter to be too lazy, and it'll go straight back to work after an overnight cleaning and sanitation as per usual.
I'll admit to being a novice at this whole brewing caper, so if you can see any problems with the above plan I'd be more than happy to hear them.

[hoppingMad]

so I figured a good litre or so of trub (is that the term?)

"slurry"

and if I use ginger beer it'll give that slight flavour edge to the finished lemonade.

that sounds fantastic to me. Good idea.

I've read that bread type yeast gives a 'doughy' flavour (who would have thought....) so I'm going to assume the same is true of beer type yeasts, and beery hard lemonade doesn't sound too appealing.

you are fine with beer yeast. It does not impart a beer flavour to the lemonade but rather more of a clean taste than bread yeast. Beer flavour in beer, comes from malt mostly, with beer yeasts contributing a very familiar and important yeasty aspect from the fermentaion of those malts. Its all just my opinion though.

[MartialAnt]

Hmm 2 table spoons isnt much. I washed all of the trub from a few brews ago. Had 16 2L pets full to start with getting it all down to 200ml of Windsor yeast. Took nearly a week to do but was worth it. That then got pitched into AG#12 + 2 DJ's of Turbo Cider. Its now in the process of being washed again & is going to be used in my next 25L of TC.
The PITA is getting all the boiled water ready to wash the yeast with.

Got same to do with Nottingham once AG#11 is done. Taking ages to ferment out. Not stuck though.

[fatcontro11er]

dont know if i should have done this but, i have ! i have both taken krausen from the top of a brew and added it to a cooled wort and also at the end of a fermantation taken around a pint of the slurry and kept it for a week or two in the fridge ands pitched that for fermenting beer !both seem to have worked fine for me in the past . the yeast was origanally abog standard dried packet of ritchies or youngs etc

[MartialAnt]

Here's the said Windsor yeast i mentioned. Should be enough for 40pints of next TC.

Undecided whether to feed it some sugar or put it away in the fridge for a week. Could feed it then drain off the alcoholic water. Then i could add some cordial juice to it. Thats an idea.

[hoppingMad]

Hmm 2 table spoons isnt much.

All my starters are now made from 1 ml of propagated frozen slurry. I believe the amount of yeast slurry saved is not critical, rather the volume of starter wort used to step up the cell count. But I'm still learning these things.

[MartialAnt]

Hmm 2 table spoons isnt much.

All my starters are now made from 1 ml of propagated frozen slurry. I believe the amount of yeast slurry saved is not critical, rather the volume of starter wort used to step up the cell count. But I'm still learning these things.

1ml. Ive plenty of Windsor if you want to borrow some.

[BeerCheez]

Thanks for all this guys! Finally, how many times can a yeast be re-used in this way? On a recent brewery tour I was told they recycled yeast five times before starting with fresh, (but they put it through filters and cleaned it up each time)

Beercheez

[hoppingMad]

Most of the reading I've done says 4-5 times as well. However I have personally only ever done 2. However I have yet to speak ( on a forum) with anyone who has actually re-used yeast so many times that they have experienced problems.
I'm not sure what homebrewer would re-use yeast more than a few times anyway when we are typically brewing so many different styles, requiring different yeasts.

Hi MartialAnt, cheers for the Windsor offer, I have not tried this yeast as yet. It is obviously a good one.

1ml is all thats needed for yeast bank freezing, I am presently holding 10 vials each of 5 strains which will probably do me for some considerable time . No more yeast cost to contend with these days, whereas formery I was having to pay NZ$ 35 for an imported activator smack pack per batch. I happily used all the dried yeasts at various times too, but am very excited about the variety and quality I'm getting with these Wyeast propagations.