how do i re use yeast

[Motorhomebrew]

Alright guys and gals. Iv been a making home brew now for just over a year now, and one thing I keep reading about is how people are re using their yeasts. Like their yeast cakes out of an fv and all that jazz. Now I find this really interesting. If I'm right does that mean I now have a black rock pilsner on the go in my FV and I used saflager S23 yeast. So can I harvest that yeast once iv finished kegging up my beer and if so how do I harvest it and how do i store it and for how long etc and then when i want to use it again how do I go about using it? And finally how many times can you use the same harvested yeast cake. Are their any advantages from re using the yeast?????? So if this all sounds silly or better still if its all nonsense lol. Any help would be great.
Cheers

 

[clibit]

The big advantage is that it's free.

When you rack your beer off the yeast sediment, leave a little beer. Swirl the FV to mix the beer and yeast. Then put the yeast into containers that have been well sterilised. I use small glass jars, and nearly fill them, to minimise air contamination. Keep them in the fridge. I get a few jars each time, and end up with too much!

This yeast can be kept for a while. If used within 2-3 weeks, you can just pitch it. We can deal with how much you pitch later. If it's older, you need to make a yeast starter, which is just a mix of water and malt extract that is boiled and cooled, to which you add the yeast a couple of days before brew day. It gets the yeast active and increases the number of live yeast cells. A starter will always improve yeast performance.

You can use 5 or 6 generations of yeast, apparently, according to the stuff I've read. But it depends on how sterile your brewing and yeast handling is. Breweries use many generations, passing yeast from batch to batch. Home brewers vary. The most I've done is about four I think. I don't usually harvest dried yeast, it's cheap and each new pack is pure. But i did use a pack of Mauribrew Weiss yeast on 3 or 4 successive brews, and I've harvested other dried yeasts occasionally. I always harvest liquid yeasts, to spread the cost.

 

[Covrich]

Great summary from Clibit, one thing I would also add which he also suggested to me for my strain was that some strains can be top cropped, depends on the strain you use though

 

[GHW]

I've just made a starter from some wyeast London ale III that I used in my boddingtons, I'm planning on using it in another bitter tomorrow or weds. It's the first time I've done it, and I also have little idea what I am up to. So...

1) should be shaking the stater several times a day?
2) how much of it should I pitch into a 12L brew? The starter is a litre of 1035 wort with half a jar of slurry added.
3) when you pitch do you just chuck the lot in, wort and all?

 

[clibit]

Good point Mr Cov, yeast taken off the top is good stuff, if it's a yeast that likes to sit on top. I was just keeping things simple.

 

[GlentoranMark]

Hi Rob, it's new to me also but what I started doing was just pitching my latest wort onto the trub of my last brew. I know I can't do it forever but if you read my thread I done it for my last brew and then used the spent grains for a weaker brew yesterday. It was grains that would otherwise threw out so it's nothing lost if it fails. With my main brew I used fresh Safale US 05 but in 3 weeks time when it comes to bottle I'll put a fresh brew onto the trub.

I'll have to start making starters though.

Just curious can you freeze yeast? And how do companies make dried yeast?

 

[clibit]

Hi Rob, it's new to me also but what I started doing was just pitching my latest wort onto the trub of my last brew. I know I can't do it forever but if you read my thread I done it for my last brew and then used the spent grains for a weaker brew yesterday. It was grains that would otherwise threw out so it's nothing lost if it fails. With my main brew I used fresh Safale US 05 but in 3 weeks time when it comes to bottle I'll put a fresh brew onto the trub.

I'll have to start making starters though.

Just curious can you freeze yeast? And how do companies make dried yeast?

Good idea to make an extra brew. If you have some DME handy you can always add some after you take the OG, if necessary.

Yeast can be frozen but you need to add glycerin, I've never done it.

http://www.homebrewtalk.com/showthread.php?t=35891

 

[clibit]

From byo.com:

Making Dried Yeast
I spoke with Bruce Patterson of the Lesaffre Group (producers of Fermentis dried yeast) about how dried yeast is manufactured.

Fermentis yeast strains are stored in a laboratory either at -80 °C (-112 °F) in glycerol or at 4 °C (39 °F) on slants. Each strain is genetically identified before it is sent to the factory for a production run. The yeast is transferred to a liquid media made from molasses (with a sucrose content of 45–55%) with added nutrients to supply nitrogen, phosphorous, vitamins and minerals. The culture is stepped up several times in the lab before being sent to the factory.

At the yeast plant, the culture enters a rapid cell production phase and the yeast are fed continuously with molasses, nutrients and oxygen. The yeast are grown in very large fermenters, much larger than at liquid yeast plants. (How big exactly is a trade secret.)

Next, the rate of cell division is slowed and, in preparation for drying, nutrients and unspecified agents are added to the yeast to help it survive the process. The yeast cells are then harvested, separated from their media and dried to a cream with between 15 and 20% solids. The cream is pressed into a cake and extruded through a mold to produce yeast “noodles.” The noodles are then dried in an air lift dryer.

In an air lift, the yeast sit on a grate and hot air is forced up through the yeast “noodles.” The yeast are churned sort of like corn kernels in a hot air popper. (An older way of drying the yeast is to put the yeast in trays and have it ride on a conveyer belt through a long oven.) The yeast are slowly dried until they contain 94% solids. The dried yeast is then vacuum packed into sachets, which have a shelf life of two years when stored under 10 °C (50 °F). The viability of the dried yeast is 86%, but each dried yeast packet contains about 10 billion living cells per gram. Thus an 11 g pouch would contain about 110 billion cells. (These are the numbers for Fermentis yeast. The numbers for Danstar Nottingham and Windsor yeasts are comparable.)

Dried yeast companies report a very low contamination rate. (Fermentis yeast, for example, reports less than 5 bacterial cells/mL of wort in adequately pitched wort.) Patterson, however, mentions that sometimes the level falls below what can be detected in the lab. And, the experience of many brewers shows that this level does not result in problematic beer.

Chris Colby would like to thank Bruce Patterson of Fermentis for his help.

 

[terrym]

I cut and pasted this into a single document for my own use from some things MyQul posted earlier on this forum. It might be a bit jumbled (that's down to me not MyQul) but here it is...
"I rinse the yeast out of the trub using spent starter wort. Basically, I put some trub in a starter then let it ferment out then use the spent starter wort to rinse the yeast out of the trub and keep the yeast under the spent starter wort (essentially unhopped beer).
*Harvest some trub (I would use the initial trub btw)
*Make a 2L starter (200g DME/2L water - boiled for 15mins to sterilize then cooled)
*Put about 400ml of trub and the starter wort in a 5L water bottle and ferment out over a couple of days, shaking the water bottle at least 4 times per day.
*Once the starter has fermented out get a couple of 2L water bottles
*Shake the starter to suspend everything in the spent wort.
*Leave it on the side for 20mins and the heavier trub will settle out to the bottom of the water bottle leaving the yeast suspended in the spent wort
*Decant the spent wort/suspended yeast into the 2x2L water bottles.
*Put the 2L water bottles in the fridge to crash out the yeast so you can now measure how much yeast you've got - Job done.
Once rinsed out I then will put the yeast into a two Ltre starter split it in two once fermented out put half in a 1Ltr starter 12 hrs before I need to pitch into a brew and put the other half into another 2L of starter two split again and do the above. I just keep doing this until I change yeast strains then start again by just overpitching a packet of dry yeast. As I'm makig a starter each time I'm going to use it, I keep the rinsed yeast in the fridge as long as I need to.
You dont have to then make a starter with the harvested and rinsed yeast, you can pitch it straight into your wort (provided you have enough). As long as it's no more than 2-3 weeks old (4 at a push)
Over the next five or so days remove the bung and swirl the demijohn round to allow air into the solution two or three times a day, this is because the yeast needs oxygen to reproduce and increase the number of viable yeast cells. Make sure not to put the airlock on any unsanitised surfaces whilst you do this, with practice you can hold the airlock whilst swirling the demijohn. Over the next few days a white layer will build up on the bottom of the vessel - that's your yeast.
Prior to pitching the yeast syphon off the spent wort and taste it to make sure it doesn't taste sour i.e. it's infected. If all is well add a litre of boiled cooled wort on brewday to wake the yeast up prior to pitching the whole lot into your cooled brew. It's as easy as that!"

 

[Motorhomebrew]

All fantastic information guys. But I do kit beers (soon to change clibit don't worry I'm on the AG soon lol ) right so at the moment I have a lager in the fv at the moment and I'm using dried saflager S23 yeast. Once iv kegged my brew and left abit of the beer in the bottom with the yeast cake can I then like cibit says harvest that into a sterile container and then can I add all of that to my next brew that I will be doing a day or so later. Like literally once iv made my new brew instead of paying nearly £4 again for another sachet I can just pour in all of my harvested yeast from my current brew? And ofcourse until I use the yeast keep it in the fridge

 

[clibit]

All fantastic information guys. But I do kit beers (soon to change clibit don't worry I'm on the AG soon lol ) right so at the moment I have a lager in the fv at the moment and I'm using dried saflager S23 yeast. Once iv kegged my brew and left abit of the beer in the bottom with the yeast cake can I then like cibit says harvest that into a sterile container and then can I add all of that to my next brew that I will be doing a day or so later. Like literally once iv made my new brew instead of paying nearly �£4 again for another sachet I can just pour in all of my harvested yeast from my current brew? And ofcourse until I use the yeast keep it in the fridge

You don't need all of it, maybe a third of it. Fermenting beer creates yeast.

 

[Motorhomebrew]

I presume you pitch the yeast at the normal pitching temp for the yeast. Also if its been in the fridge van you use it straight from the fridge or do you have to bring it up to room temp or anything before?

 

[jeg3]

It's worth getting the yeast to room temp to reduce temperature shock. Although I've pitched yeast straight from the fridge before it takes a while to wake up.

I've recently successfully cultured Wye Valley yeast from a bottle of Butty Bach which happens to be a top cropping variety, and it first in AG #9

I cropped from AG #9 and stored in the fridge for a month. Pitched into AG #10 last week and then today cropped from that and pitched directly into AG #11 (which I started this morning). The results were fairly instant, no lag at all.

Harvesting from the yeast cake will give equally good results

 

[Motorhomebrew]

Well iv just checked the gravity on this beer and its down to 1.024 so its deffo working. I did give it a little taste and I don't know weather this was because there were so much yeast in the sample but it had a strange creamy taste to it. This beer will be given the same treatment of upper the temp a few degrees to give it a temp rest so fingers crossed it turns out ok

 

[TartanSpecial]

I use small glass jars, and nearly fill them, to minimise air contamination. Keep them in the fridge.

I put the harvested yeast into 250-1ltr PET bottles filled to the top. I have found that some continue to produce a little gas even in the fridge so I need to release pressure after a few days before they finally settle down and sleep (wlp 028 especially so). I was worried that glass jars might crack open.

 

[clibit]

I don't tighten the lids until they have settled down.

 

[jeg3]

I add about 200ml of sterile 1.040 wort, ferment it out then store in the fridge. If I keep it longer than 3 weeks I make a starter