A Different Re-using Yeast Question

[adam]

G'day Guys

about 2 months ago i saved some of the slurry (mixed with some water) from an APA using US-56 yeast.
My questions are is it still OK to use - its been in a sealed container in the fridge for this time. and
as the slurry in the container has seperated to look like the bottom half is just slurry and the top half is much clearer - should i pitch the lot or should I poor the clear stuff off first or should I only use the clear stuff??
I hope this makes sense.
Also, should i let it warm up to the temp of the wort before pitching?

thanks
adam

 

[pint of lager]

Yeast die off very quickly after they stop fermenting. After two months, there will not be very much viable yeast in your slurry, certainly not enough to provide a quick start to your ferment. If you want to use it, make a starter of 100 gms DME dissolved in a litre of water, boil of 20 minutes, chill, pour into a sanitised starter bottle and add half of your slurry.

When this is actively fermenting, you can then pitch it to your wort. If it takes more than four days to fire your 1 litrestarter wort, throw the lot away.

American 56 is available as a dried yeast from Brewcellars in a decent sized sachet and offers a good alternative to liquid 1056.

It is good practice to warm any yeast gently to the same temperature as your wort, dried or liquid.

 

[Mr Bond]

Totally agree with POL's excellent info.
But in all honesty US 56 is usually under/around $5 for a fresh sachet that is guarateed to have the required numbers to give a good ferment.It's prolly not worth the stuffing around to rouse it up.Collecting,washing and starting up specific liquid strains is worth the effort,but for a dry yeast its a waste really.
For the record I do reuse my US56(dry) culture but its only if I'm pitching consecutive brews onto a yeast cake,or saving some slurry and using it within a 7 day period.

 

[Trough Lolly]

Just to add to the confusion (!?!) I'd say you can easily do a mini pseudo wash and make a starter. Why? Because I've been reading some tech articles in the US that confirmed my suspicion that the Chico Ale yeast strain (US-56 or Wyeast 1056 etc) actually improves in subsequent uses.
I've just used the same slurry for a third batch straight (the last two in the same fermenter!) and it's currently pushing the water out of the airlock as I type!! I had airlock action within 5 minutes of pitching the wort.
Don't add the slurry to the wort you've made - as PoL suggests, you need to give it a kick in the pants to see if it's still viable - but before you make the starter:
1. Decant as much clear fluid off the slurry as you can,without losing any of the slurry, (if it smells foul, stop here and go to the shop!)
else
2. Let the yeast slurry come to room temps.
3. Cleanly / Aseptically add 300ml cooled pre-boiled water to the container (via a sanitised funnel and swab the water container's lip) and swirl the lot to re-suspend the slurry and let it rest for about 15 mins.
4. The heavier slurry and trub will sink first leaving behind a milky yeast laden solution - carefully and cleanly decant that milky solution into the starter wort, leaving as much of the slurry behind as you can. It doesn't matter if you only get half of the 300ml into the starter - it's the suspended yeast that you're after, not the slurry and you will get population growth in the fresh starter if there are viable cells in the original "yeast milk".
5. Carry on with the starter, observe and if it's dead as PoL says, then cross it off to experience and use a fresh sachet.
I have noticed that some strains reward you for repitching and one of them is the Chico Ale strain - which is unusual for a relatively clean fermenting ale yeast strain...
Cheers,
TL

 

[adam]

thanks for the replys guys and thanks for the detailed procedure Mr. Lolly - this was what I needed.

adam

 

[Daniel.lear]

G'day gurus

on a slightly different tangent, i currently have an IPA that im about to rack to seccondary, and was thinking of putting a Black Rock Dry Lager on the yeast bed ( US-56 ). My question is will using the dry enzyme with the old yeast still be viable, and will it affect it in any way?? :unsure:

PS first ever post on AHB :beerbang:

 

[pint of lager]

Hi Leary,

Good question on your first post. The people that take a few weeks to ask their first question usually have done lots of reading of the site.

By pitching onto a yeast cake, you have a huge quantity of yeast working for you. During fermentation, yeast produce heat, too many yeast working for you will generate too much heat and the temperature of your brew can climb rapidly. If you have very good control of your fermnet temp, such as in breweries with thermostats, cooling coils etc, go for it.

If, like most of us homebrewers, you don't have good control and rely on air temp, consider transferring your yeast cake to a sanitised jar (boil some water in a kettle, let it cool to 20 deg, pour about 1/2 litre onto the cake, swirl swirl swirl and transfer to a sanitised jar), cleaning out the fermenter and only pitching say 1/4 of a cup of the yeast cake or slurry into your next brew. This will be enough for it to take off like a rocket.

There shouldn't be any problems using a dry enzyme in the next brew. Obviously, don't use the slurry from a brew with dry enzyme in it, as this will then act on the next brew.

 

[Borret]

There shouldn't be any problems using a dry enzyme in the next brew. Obviously, don't use the slurry from a brew with dry enzyme in it, as this will then act on the next brew.

POL,

Is that fact or assumption.

To my way of thinking the enzyme is working in a similar way to amylase in a mash to break down more complex sugars to simple more fermetable ones and hence the dryer finish. Just as grain has only a certain amount of diastic power I would think that the dry enzymes in a pack would be similar with regards to their lifespan/ potential use. I would think there would be very little if any viable enzymes left over at the end of a brew as they do not reproduce like yeast.

That is just my thoughts and I may be wrong but I thought I'd queary it. Do you have evidence/information that suggests otherwise?

Brent

 

[pint of lager]

Borrret, it is an assumption. I rarely use dry enzyme and also now rarely repitch slurry.

Enzymes in the mash are destroyed by heat, whereas the enzymes in a ferment are different to those in the mash and are also not being acted upon by heat.

 

[Daniel.lear]

thanks POL just the info i was after. as for the enzymes i hadn't planned on useing it on subsequent batches so thats not to much of an issue. perhaps a few of the more scientific members on the forum could provide some info on enzyme life?

 

[Borret]

Borrret, it is an assumption. I rarely use dry enzyme and also now rarely repitch slurry.

Enzymes in the mash are destroyed by heat, whereas the enzymes in a ferment are different to those in the mash and are also not being acted upon by heat.

POOL

They are still enzymes as oppsed to be fungus like yeast.

Just as the dry enzyme is not destroyed by the heat of fermentation, so amylase is not destroyed by the heat they are active at ... hence we have a 'mash out' if required which does destroy the excess at the end of the mash..

My point is that the likes of munich that are said to have enough enzymes (diastic power) to convert only itself will have no enzyme activity left over to act on other things (ie adjuncts). In the same way the dry enzyme is a measured dose to do it's job and break down what it needs too. Short of adding a large amount there is probably very little left over after the ferment.....

Also.... does an enzyme stay suspended or settle out like yeast. If indeed it is in suspension still at the end of primary then very little proportion of it would be left in the yeast cake. This is particularly relevent to a kit brewer who may just bottle straight from primary before everything has settled properly.

I can't say that I would re-use such a yeast cake myself but I still don't 'recon' the enzyme bears much threat

Brent

 

[Darren]

Borrett, Pint of lager,


Enzymes are proteins and would likely settle onto the cake under lagering conditions. Whether they will still be active weeks after pitching is debatable.
Certainly, if they are still active they will be in the cake, regardless of settling, and would the potential to munch through the sugars from the next beer.

I guess it would be advisable to wash the cake with sterile water to eliminate this possibility.

cheers

Darren

 

[poppa joe]

HEY FELLAS...
When you say"pitched onto cake" Do you mean remove the slurry into sterilized jar.
Do the brew(k&k here..)
Then wack the yeast back in...??????????
Cheers
PJ

 

[Darren]

Remove some of the yeast into a sterilised jar is the best option. Alternatively, you can remove some of the yeast from the fermenter or simply throw your next beer onto the whole yeast cake. If you do the later you will want to ensure that your wort is below or at the best ferment temps. If it is over the optimal ferment temp it will go off like a bomb. Had a 1.100 imperial stout finish in 24 hours once when pitched too warm onto a cake.
Biy was that headache material.

cheers

Darren

 

[poppa joe]

Darren..
Temp. was my concern about the method..
Best way ...possibly prepare wort in another fermenter..Pitch onto that..
Cheers
Pj