Old yeast starter - dispose or keep?

[timtoos]

I made up a yeast starter about 3 or 4 months ago. It was a large 3l starter for a lager (Wyeast 2124)

Anyway, life got in the way of brewing and its sat in its container in the fridge since it was finished. To be honest I dont think I will brew in the next month or so either!

Would the yeast still be ok or does it need disposing of? Im worried about yeast health and bacteria. Its stored in the same container the starter was prepared in. If it's ok I will leave and make another starter as and when required.

Thanks

 

[SmallSpacesBrewing]

The yeast is probably dead by now, but you could try and revive it with a new starter, that is if it still smell ok.

 

[johncrobinson]

My late Father used to keep his wine starters going for several years at a time.
One i recall in the 1980s for over 10yrs.!!!

Now i am not advocating this,Just pointing out it can be done.

 

[matt76]

I would expect it to be absolutely fine. My concern would be what liquid the yeast has been stored in, what kind of container etc, but I would be very optimistic about being able to revive it.

I've recently resurrected some WY1318 that had been stored in the fridge in a sealed plastic jar under beer for over 12 months - it woke straight up once I put it in some fresh wort.

In addition, other forum members have fairly recently woken up 40 year old yeast from the dregs at the bottom of some very old bottles of beer.

 

[timtoos]

Its sat in a large starter vessel (5l) and the liquid is spent dme used for the starter.
This is the area I am concerned with too and any bacteria/contamination risk this causes.
I have attached the starter vessel with the yeast and liquid volumes to see. The top of the vessel is a plastic screw type cap which I think is fastened right down.

 

[SmallSpacesBrewing]

Its sat in a large starter vessel (5l) and the liquid is spent dme used for the starter.
This is the area I am concerned with too and any bacteria/contamination risk this causes.
I have attached the starter vessel with the yeast and liquid volumes to see. The top of the vessel is a plastic screw type cap which I think is fastened right down.

Should be fine after being stored in a container like that. I've revived a kveik yeast after over a year in the fridge. No problem.

 

[timtoos]

Great stuff, many thanks. Is it best leaving it in there until I need it and then make another starter?

 

[matt76]

It looks like it's stored under beer which is the best place for it (according to Denny Conn at least) so yeah I'd leave it until you need it. Never any guarantees of course but I'd have thought you'd be OK.

 

[timtoos]

Thanks all. I will keep it until it's required.

 

[foxbat]

Great stuff, many thanks. Is it best leaving it in there until I need it and then make another starter?

Leave it there until you need it. Then use an online calculator to work out how big your next starter needs to be. You're treating this starter as the "yeast pack" and using the number of cells you made up as the "initial cell count" and the date you made it as the "manufacturing date".

I would make up the new starter DME in a fresh flask then decant off 90% of the liquid you've got now, use the rest to swirl up the yeast that'll be quite well stuck to the bottom by then and tip into the new flask.

 

[timtoos]

Leave it there until you need it. Then use an online calculator to work out how big your next starter needs to be. You're treating this starter as the "yeast pack" and using the number of cells you made up as the "initial cell count" and the date you made it as the "manufacturing date".

I would make up the new starter DME in a fresh flask then decant off 90% of the liquid you've got now, use the rest to swirl up the yeast that'll be quite well stuck to the bottom by then and tip into the new flask.

Great stuff, will do.
On the subject of yeast, do you think there is much difference in dried and liquid? Ive used liquid for a while now but it seriously needs much more brew day planning an dressing about.

I have done the Timmy Taylors landlord a few times, every time with the Yorkshire yeast. I cant imagine what this is like without using this said yeast.

 

[foxbat]

Great stuff, will do.
On the subject of yeast, do you think there is much difference in dried and liquid? Ive used liquid for a while now but it seriously needs much more brew day planning an dressing about.

I have done the Timmy Taylors landlord a few times, every time with the Yorkshire yeast. I cant imagine what this is like without using this said yeast.

That's a perennial question on these forums. I think there is, and liquid yeast is all that I use. I enjoy making up a starter and seeing the yeast grow so that's no bother for me. However there's a lot of dry yeast strains out there these days and many breweries use it so it can't be all bland and characterless. I would imagine though that Wyeast 1469 is a hard one to beat for a TTL clone.

 

[matt76]

That's a perennial question on these forums. I think there is, and liquid yeast is all that I use. I enjoy making up a starter and seeing the yeast grow so that's no bother for me. However there's a lot of dry yeast strains out there these days and many breweries use it so it can't be all bland and characterless. I would imagine though that Wyeast 1469 is a hard one to beat for a TTL clone.

Indeed, this is a discussion @foxbat and I had briefly a little while ago.

I started out my brewing career using Wyeast, both fresh packs and grown in starters. But then I got fed up with the advanced planning required and switched to dry yeast - the advantage being I can have loads of packs in the fridge ready when I need them and which will last yonks. As foxbat says above, he likes the faff - his choice, his beer so more power to him

The main advantage of liquid yeast seems to be the much wider variety of strains available:
- E.g. a really, really good dry English ale strain (such as WY1318, WY1469) seems to have been missing for many years. But dry yeast is improving in this regard. I did a comparison recently between Lallemand Verdant IPA and WY1318 and couldn't tell them apart (not totally conclusive though, more comparisons needed). MJ M36 could also be a very good shout for an English ale strain.
- Also I wonder if this variety is overplayed a bit - each to their own, but I would advocate for sticking to a limited number of strains (whether liquid or dry) so you get to know their characteristics better and can be more consistent in your brewing (interesting article on this here).

Ultimately I think it's useful to have experience of both to give you flexibility - dry yeast is really convenient, but on the other hand if one didn't have experience of messing around with starters and liquid yeasts then the task of harvesting yeast from commercial beer (as I know foxbat has just done with Fuller's 1845 for example) would probably seem a lot more daunting.

 

[saccharomyces]

It looks like it's stored under beer which is the best place for it (according to Denny Conn at least) so yeah I'd leave it until you need it. Never any guarantees of course but I'd have thought you'd be OK.



Actually, Denny got that information from me. Denny has been one of my biggest champions. I used to post as S. cerevisiae on the AHA forum and as YeastWhisperer on Jim's Beer Kit. Yes, the best way to store cropped yeast is under beer, which includes fermented out starter media. Why? Well, it has to do with how a yeast culture shuts out competitors. The first thing that a yeast culture does is consume all of the dissolved O2, shutting out aerobic microflora. The culture simultaneously lowers the pH to close 4, which shuts out pH sensitive microflora, including the bad boys, the pathogens (e.g., Clostridium botulinum cannot replicate below pH 4.6). Finally, it produces ethanol, which is toxic to all living organisms at given levels. Throughout history, table-strength beer was preferred to water because water often contained waterborne pathogens. Cholera is a prime example of a waterborne illness. John Snow determined that cholera was a waterborne illness because of the pump near the Lion Brewery on Broad Street in London. People all around the brewery were getting sick, but none of the brewery workers contracted the disease. That was due to the fact that the brewery workers received rations of beer.



Rinsing yeast with boiled water is one the worst things a brewer can do to his/her culture because it removes the protective environment the culture built for itself. There is mounting evidence that the reason why brewer's yeast strains are Crabtee positive is because preferring fermentation over respiration above the Crabtee threshold of 0.2% w/v (0.2g of DME in a 100ml solution or a specific gravity of 1.0008) was an adaptive change to give yeast cultures the competitive advantage outlined above. Pitching rates are about pitching enough yeast cells to ensure that the pitched culture out competes native microflora. Anyone who wants to know more about how yeast cultures grow should read my blog entry entitled "Yeast Cultures are Like Nuclear Weapons" on the Experimental Brewing website (Yeast Cultures are Like Nuclear Weapons | Experimental Homebrewing).

 

[matt76]

Thanks for the clarification @saccharomyces , your priority is duly noted :hat:Will check out the link, thanks

(and if I recall correctly, I think Drew & Denny also cited you in "Simple Home-brewing" as an early advocate of vitality (a.k.a. shaken not stirred) starters)

 

[saccharomyces]

I invented the "Shaken, not Stirred" (SNS) starter method when I first started to brew back in the early 90s. I did not set out to create a new way to prepare a starter. It was pure serendipity much in the way that Alexander Fleming discovered penicillin; namely, a trained, questioning mind observing a phenomenon. It happened because I broke my main starter container. I was using a 48oz Ocean Spray glass bottle to make one quart starters. I went to make a starter and discovered a crack in it. The only other glass container I had on hand was a one-gallon apple juice jug (demijohn) that I repurposed for making mead. I was a gym rat from my teens to my teens up through my thirties, which meant that shaking the a starter like it owed me money was par for the course. Shaking a quart of starter media in a 48oz bottle does not produce the same effect as shaking a quart of starter media in a one-gallon jug, irrespective of how hard it is shaken. I noticed the change in performance right away, but I had to think about the phenomenon for a while before it dawned on me that the foam was the key to the improvement. Shaking a liquid into foam results in a huge increase in specific surface area in which oxygen can diffuse. Basically, SNS is a poor man's O2 bottle and diffusion stone. I have since moved on to using a 5L borosilicate media bottle and the metric system to make 1L starters because preparing weight by volume starter media is much simpler using the metric system than using U.S. customary units because one U.S. fluid ounce weighs more than one U.S. dry ounce.

Anyway, I did not share my starter method with others until 2015 (I took a hiatus from the hobby from 2004 to 2013 to focus on my children when they were young). I received a lot of pushback when I first posted SNS on the AHA forum. A couple of forum members tried my method with very good results. However, acceptance did not occur until Denny Conn tried it and wrote a blog entry about his experience entitled "Old Dog...New Tricks" on the Experimental Brewing website (Old Dog...New Tricks | Experimental Homebrewing). I also posted my starter method on Jim's Beer Kit a few months later. A few years later Denny asked me to write something about myself because he and Drew were going to include SNS in an upcoming book, which we now know as "Simple Homebrewing."

 

[matt76]

Fascinating stuff @saccharomyces , I hadn't particularly appreciated the importance of the ratio between the volume of your SNS vessel and starter medium.

To be honest I rarely make a starter these days - I've done it in the past but since switching to dry yeast (for convenience, less planning ahead required and also because I'm lazy) I find half a pack seems to be sufficient for my 10-12L batches (or a full pack for lagers or high gravity ales). That said, I plan to use some WY1318 slurry soon and was planning on using SNS to wake it up when the time comes.

I'm curious to get your thoughts though on a couple of perennial questions/discussion points actually:

Opinion seems to be divided but personally I don't bother to rehydrate dry yeast, I just rip and dump (you can blame Denny for that as well!). Is this something with your expertise you would say is a really bad idea?

Reusing the yeast cake - I've done this a few times with no issues, literally bottling the first batch and then dumping the fresh wort straight into the same FV onto the entire yeast cake. I recall Denny saying on the podcast he had tried it and recommending using only 1/3 of the yeast cake simply on the basis that he found this produced the best tasting beer (in his opinion). Do you have a view on the wisdom (or not) of this? It's relevant for me at the moment as I have a low gravity stout just finishing off right now (OG 1.045) and I plan to reuse the yeast cake for a high gravity stout (probably OG 1.080 or so). In this case there's no dry hops and virtually no trub gone into the FV so I expect the yeast cake to be pretty darn pure.

Cheers,

Matt

 

[saccharomyces]

I have only recently started to use dry yeast again after swearing it off for 27 years. The reason why I learned how to do single-cell isolation and make plates and slants (slopes) is because the state of dry when I started brewing in early 1993 was just dreadful. It drove me to isolate and keep my own bank of yeast cultures on slant, a practice that I continue up until a couple of years ago.

That being said, from what I have seen pitching temperature is critical if one does not rehydrate first. Dry yeast wants to be rehydrated at atleast 20C. Whether that is done in warm water or warm wort does not matter.

I do not recommend using the entire yeast cake if one plans to serially re-pitch. Serial re-pitching requires a healthy amount of new cell growth during each fermentation cycle. That is why it is better to underpitch than overpitch. When repitching ale, I would pitch no more than 180ml of thick slurry per 23L. I would bump that figure up to 270ml for lager. Pitching the entire cake is going to cause the average age of the cells in one's culture to increase with each repitching.

 

[matt76]

When repitching ale, I would pitch no more than 180ml of thick slurry per 23L. I would bump that figure up to 270ml for lager.

Would you still stick with those figures (180ml per 23L for ale) for higher gravity wort, e.g. OG = 1.080?

For my smaller batches this is around 100ml or less - really not much at all! But then I guess you can fit a lot of tiny yeast cells in to every ml!

 

[johncrobinson]

My interest is wine rather than beers.

However during lockdown last year i could not get my favorite yeast,So ended up using bread yeast,Not a great success.!!!!

I have now got a small sample of my yeast,So i intend to follow in my Fathers footsteps and home culture this yeast.