Harvesting slurry without using a secondary?

[Raisoshi]

I had a Dry Stout sitting on the yeast cake in primary for 2 months with Nottingham yeast, I harvested the slurry but it got me thinking. Is that slurry viable, or should I have harvested it right after primary fermentation was over?

Did the same with a 3 week old APA with US-05 last week, the yeast has been sitting in the fridge for this 1 week and I plan to use it this weekend, will I encounter any problems?

 

[JonM]

The yeast should be fine. No need to use a secondary in order to harvest the yeast.

I assume the 05 has been in a mason jar or beer bottle or something, and not just sitting in a near-empty fermenter though, right?

 

[ericbw]

That's the only way I do it. It's safe in the beer.

 

[flars]

This HBT link has some good information. Check out the last post @WoodlandBrew.
https://www.homebrewtalk.com/f163/saving-yeast-how-much-save-512185/#post6632389

 

[trentm]

I had a Dry Stout sitting on the yeast cake in primary for 2 months with Nottingham yeast, I harvested the slurry but it got me thinking. Is that slurry viable, or should I have harvested it right after primary fermentation was over?

Did the same with a 3 week old APA with US-05 last week, the yeast has been sitting in the fridge for this 1 week and I plan to use it this weekend, will I encounter any problems?

I guess almost any yeast will make beer. My disabled alcoholic buddy back in rural Oklahoma gets whatever canned fruit he can get through the USDA commodity program, throws in some old bread and next week he's drunk. So that's one extreme. The other is the commercial brewery who wants to pitch yeast from one fermenter to the next and will not pitch even properly handled yeast that's over one week old. Or have their new pitches shipped overnight cold direct from the propagator. As homebrewers we have to find some middle ground as the healthiest yeast are not available to us unless we want to propagate from storage using laboratory methodologies. I have chosen this extreme and it has taken my beer to new levels.

I believe there is much more to great yeast than viability. Say you are lucky enough to have a pitch of yeast that is 90% viable (according to Mr Malty this is a vial of yeast 10 days from manufacturing date). Ten percent of those yeast are dead, probably from starvation. Now let's say you want to pick a soccer team, or whatever, would you look for athletes who were confined to an environment where 10 percent of the people had starved to death? What is the health of the other 90 percent and would they be able to even complete a soccer game?

Below is a graph illustrating the effects of cold and not so cold storage of yeast in relation to intracellular glycogen content. The standard glycogen content for a healthy pitch is 20%. As illustrated, after only 24 hours at 15C (59F) the yeast is approaching the borderline. Even after a week at 4C the yeast is again near the limit. Think of the glycogen content after 2 months at whatever temp your primary has been conditioning.

Note: Glycogen is the main carbohydrate yeast use to survive during storage and for energy during the lag phase of a fermentation.

 

[ericbw]

I guess almost any yeast will make beer. My disabled alcoholic buddy back in rural Oklahoma gets whatever canned fruit he can get through the USDA commodity program, throws in some old bread and next week he's drunk. So that's one extreme. The other is the commercial brewery who wants to pitch yeast from one fermenter to the next and will not pitch even properly handled yeast that's over one week old. Or have their new pitches shipped overnight cold direct from the propagator. As homebrewers we have to find some middle ground as the healthiest yeast are not available to us unless we want to propagate from storage using laboratory methodologies. I have chosen this extreme and it has taken my beer to new levels.

I believe there is much more to great yeast than viability. Say you are lucky enough to have a pitch of yeast that is 90% viable (according to Mr Malty this is a vial of yeast 10 days from manufacturing date). Ten percent of those yeast are dead, probably from starvation. Now let's say you want to pick a soccer team, or whatever, would you look for athletes who were confined to an environment where 10 percent of the people had starved to death? What is the health of the other 90 percent and would they be able to even complete a soccer game?

Below is a graph illustrating the effects of cold and not so cold storage of yeast in relation to intracellular glycogen content. The standard glycogen content for a healthy pitch is 20%. As illustrated, after only 24 hours at 15C (59F) the yeast is approaching the borderline. Even after a week at 4C the yeast is again near the limit. Think of the glycogen content after 2 months at whatever temp your primary has been conditioning.

Note: Glycogen is the main carbohydrate yeast use to survive during storage and for energy during the lag phase of a fermentation.

You should be a better friend, maybe get him to a meeting?

This graph (from?) refers to aerobic conditions. Is sitting in a beer aerobic or anaerobic?

Also, I understand that the yeast need the glycogen during storage, but after pitching, don't they have other carbohydrates available to them?

If a group of people saw their friends starve to death, and then were given food, wouldn't they play a better soccer game? Their enthusiasm would carry them even further. And they would get to eat while they played.

Again, during storage is one thing - and it affects viability. But once it is pitched, it seems like there are other factors at work.

 

[trentm]

You should be a better friend, maybe get him to a meeting?

This graph (from?) refers to aerobic conditions. Is sitting in a beer aerobic or anaerobic?

Also, I understand that the yeast need the glycogen during storage, but after pitching, don't they have other carbohydrates available to them?

If a group of people saw their friends starve to death, and then were given food, wouldn't they play a better soccer game? Their enthusiasm would carry them even further. And they would get to eat while they played.

Again, during storage is one thing - and it affects viability. But once it is pitched, it seems like there are other factors at work.

Maybe I am not the best at encouraging people to take yeast health into consideration. I have learned the importance first hand and want to spread the news about the one thing that has done more for me to brew better beer than any other. But for some reason people seem to be resistant to my evangelizing the good news. It is almost as hard as trying to get a very good friend to do something about a drinking problem. I have tried very hard on both accounts and in both cases have only resulted in failure.

You are right that under aerobic conditions, yeast use more glycogen compared to anaerobic conditions. However the supplies are used in both cases and temperature also plays a critical role. Here is a link to where I clipped the graph: http://www.mbaa.com/districts/michigan/events/documents/2011_01_14yeaststoragefermentation.pdf. Here you can also find a graph that compares glycogen use under aerobic and anaerobic conditions.

This presentation is aimed a commercial breweries and I understand that some aspects of commercial production do not apply to homebrewers. For instance the part about heat building up in the cone of a large fermenter is not an issue for homebrewers. However there are other reasons mentioned in the presentation that do apply to us in regards to his statement “If the yeast is down – get it out of the beer”.

Regarding glycogen during the lag phase: You can find some information within the linked presentation also here: http://www.howtobrew.com/section1/chapter8-2-1.html and here: https://www.wyeastlab.com/he-yeast-fundamentals.cfm

I believe that for homebrewers acquiring fresh, healthy yeast is the biggest challenge we face. Certainly a look through this forum emphasis this. Certainly yeast that has sat for weeks or months in fermenter may be a better option than the old mishandled vials or packs available to us. Many if not most homebrewers have never had the opportunity to brew with a pitch of yeast that has been freshly produce in a lab or yeast that has, within the last day or two, finished a healthy fermentation. Perhaps that's better because once you go fresh, you're done with the rest.

 

[Raisoshi]

I use a closed PET bottle sanitized with an iodine solution to store the harvested yeast. I know it's not ideal but I don't have mason jars handy for this. Would boiling a beer bottle be a better fit? Should I cap it or use the tin foil thing(wouldn't that let outside air in leading to chance of contamination?).

One other thing then if it is still pretty viable, should I make a yeast starter for the slurry? Maybe reverse calculate the amount of yeast I need to end up with the right amount at the end of the starter?


EDIT: OH and thanks for the replies, this has been very enlightening.

 

[estricklin]

I use a closed PET bottle sanitized with an iodine solution to store the harvested yeast. I know it's not ideal but I don't have mason jars handy for this. Would boiling a beer bottle be a better fit? Should I cap it or use the tin foil thing(wouldn't that let outside air in leading to chance of contamination?).

One other thing then if it is still pretty viable, should I make a yeast starter for the slurry? Maybe reverse calculate the amount of yeast I need to end up with the right amount at the end of the starter?


EDIT: OH and thanks for the replies, this has been very enlightening.

2 months is definitely getting out there in my experience, and I mean the kind of experience where I ended up with...not so good beer. Maybe it will, maybe it won't?

The answer is what you yourself suggested; take out an insurance plan and make a nice starter and you should be fine. Some yeast strains store better than others, and who knows how healthy it was or wasn't before or after you pitched it, lots of real world variables in there.

 

[Raisoshi]

Okay so I have about 1.4 liters of 1.045 starter ready for pitching the slurry. I let it compact for a few days in the refrigerator and decanted all the liquid on top so it's pretty thick. Was thinking about adding 140ml but would that be too much? This is assuming a 2.5million cells/ml, is that about right for a thick unwashed slurry?

 

[philipCT]

Maybe I am not the best at encouraging people to take yeast health into consideration. I have learned the importance first hand and want to spread the news ...

so trentm, I'm all about making big starters to pitch into my painstakingly brewed beers, but I am sensing there's more to your methods and I'm all ears.

What you are saying about the good yeast bring the primary challenge to homebrew ers resonates with me.

Can you share more about your methods? I've upped my game in a lot of areas, and I am seriously all ears on this.

Also, having had experience twelve stepping a close friend, don't beat yourself up. You know the person has to be ready for the message. It's not all about you. Peace.

 

[trentm]

so trentm, I'm all about making big starters to pitch into my painstakingly brewed beers, but I am sensing there's more to your methods and I'm all ears.

What you are saying about the good yeast bring the primary challenge to homebrew ers resonates with me.

Can you share more about your methods? I've upped my game in a lot of areas, and I am seriously all ears on this.

Also, having had experience twelve stepping a close friend, don't beat yourself up. You know the person has to be ready for the message. It's not all about you. Peace.

Sure, but first let me say thanks for the kind words. The guy I mentioned has been my best friend for 53 years, we are now 58. I don't think he will make it to 60.

I really go to the greatest extreme for yeast preparation of any homebrewer I know of and I am sure this method is not for the average homebrewer just looking to make an easy batch of beer. However for the committed brewer who is ready to take the hobby to the highest level possible, this method can make that achievable. I do brew Belgians exclusively and perhaps these benefit more from high quality yeast than some other styles but I believe all styles will gain from great yeast.

My methods are adapted from my work as a plant pathologist (the study of plant diseases). But I think they are very similar to the way a commercial yeast lab would produce yeast. As part of my work as a plant pathologist, I would grow up cultures of various plant pathogens (typically bacteria or fungi) from storage, either in water, slant, or cryopreserved and inoculate healthy plants to study the effects of a challenge from a certain pathogen. To make these experiments publishable, strict guidelines are followed to to ensure repeatability.

To begin you need a source of yeast (any source will work). I have isolates from 5 different Belgian Strains; of those I cultured four from some of my favorite Belgians, one I got in a trade from "Worthaug" on this forum. But there is really nothing magic about isolating your own yeast, the strains from commercial yeast companies can be very good. I store my strains on slants but many people have reported good results by freezing in glycerine in a home freezer. You could even do this from a vial or pack of yeast without worrying about storage, it's just more expensive in the long run.

Now for the process: Using an inoculating loop take a very small amount of yeast from your source (if you can see it on the loop, it's enough) and dilution streak it onto a media plate to form single colonies of yeast. After 3 to 4 days growth on the plate select a few (4-8) nice looking colonies and using your loop transfer the whole colonies into 7 - 10 ml of wort (I use a 15 ml disposable centrifuge tube). Shake the tube as often and as hard as possible over the next 12 to 18 hours (strain and temp dependant), leaving the cap loose between shakes. When the a good layer of yeast has formed at the bottom of the tube and the wort begins to clear from the top (just a bit of clearing in top few millimeters) the culture is ready for the next step. Each of the following steps can be from 4 to 10 fold increases (some people have reported success using as much as a 100 fold increase for the first step). A seven fold increase seems to work best for me but smaller increase are fine, whatever fits your final volume the best. Too large of a step creates a longer lag time and more potential for infection.
Back to the next step: From the 15 ml centrifuge tube transfer to ~35ml of wort in a 125 ml flask with a stir bar (flask size can vary but try to use half or less of the total volume of the container). Incubate on a stir plate until you feel you have completed about 75% of the fermentation (it take some practice but can get an idea from the cloudiness of the culture (there is plenty of room for error if you have not planned too large of a step increase). Now it's ready to move to the next step and I would use ~250 ml of wort in a 500 or 1000 ml flask. When ready this volume will take you up to 1700 ml pitch.

Each time you transfer to the next step, just pour the stir bar into the next flask and incubate on the stir plate at ~75F with a very strong vortex. Good aeration of a culture is, in my mind, the most important variable you can control when propagating yeast. I wish I had words to describe just how important but suffice it to say with good aeration throughout the culture will achieve many more, very healthy cells. Keep in mind that growing yeast produce a lot of CO2 and removing that from your flask and bringing in an adequate amount of O2 takes a strong vortex. It also helps to keep your flasks at half volume or less.

Aseptic technique and procedures are critical throughout the process.

Culturing yeast this way will produce many more cells than just making a starter from a vial or pack because you are using optimum pitching rates for each step. This along with good aeration, cultures of all my Belgian strains (with one exception) will produce on average 300 million cells per ml (this is strain dependant and one of my strains will only produce ~200 million cells per ml). So for most Belgian strains, culturing using this method will produce 300 billion cells per liter.

I italicized some of the terms that may not be familiar to some people, a google search may help to define those terms.

 

[philipCT]

Sure, but first let me say thanks for the kind words. The guy I mentioned has been my best friend for 53 years, we are now 58. I don't think he will make it to 60.

I really go to the greatest extreme for yeast preparation of any homebrewer I know of and I am sure this method is not for the average homebrewer ...

Dude. Seriously. You are a scientist.

I'd like to think I could do all that, but I believe you have training and skills that you are making light of. I would need to be baby-stepped into that level of yeast work.

I've read about some of the practices you mention (looping, slanting) but I've never tried any of it. I also know that people who do this level of yeast work
also observe other practices like working next to an open flame (bunson style) in order to maintain an updraft.

Not sure I actually have the refrigeration that would be required to maintain several colonies if I decided to do it. Also, we lose power here in the Northeast (like we're probably about to lose power for a day or two in this big ass blizzard that's headed our way tonight) and I'd be afraid that I'd lose a all my colonies representing a tremendous amount of work if that happened. Are you ever concerned about that?

I assume you have a microscope and cell counting gear also?

Anyway, thanks for sharing the insight into advanced yeast propagation. You should make a series of videos!

 

[trentm]

Dude. Seriously. You are a scientist.

I would need to be baby-stepped into that level of yeast work.


Not sure I actually have the refrigeration that would be required to maintain several colonies if I decided to do it. Also, we lose power here in the Northeast (like we're probably about to lose power for a day or two in this big ass blizzard that's headed our way tonight) and I'd be afraid that I'd lose a all my colonies representing a tremendous amount of work if that happened. Are you ever concerned about that?

I assume you have a microscope and cell counting gear also?

Anyway, thanks for sharing the insight into advanced yeast propagation. You should make a series of videos!

Well yes, but we often hire high school or early college interns who, with minimum training, do this kind of work. If you could get some hands on training you could pick it up in a couple of hours.

Refrigeration is a concern. I'm fortunate (in this aspect) to live on the central coast of CA where we have a very moderate climate (until the next "big one"). Unless you were out of town, the yeast can be kept short term on ice.

Yes, because I no longer have access to a lab, last year I bought a cheap (er) microscope and stuff for cell counting.

Maybe someday I'll do some propagation videos. It's really a shame that healthy fresh yeast are such a challenge for homebrewers.

 

[kirkm89]

I tried doing something like this out of the primary on my last IPA and WOW, amazing results!

Original batch was a 5 gallon 1.055 OG IPA using one 11g package of re-hydrated Nottingham. After two weeks in primary, boiled about 3/4 gallon of spring water, cooled to room temp, and dumped it onto the yeast cake after racking. Swirled to mix yeast into suspension, then let carboy sit for about 10 mins to let the big stuff settle out. Poured as much of the slurry as I could into a mason jar sanitized with Star San. Covered and let that sit for ~15 minutes. Small amount of beer was on top, poured that off. Pitched about 1/2 pint of the remaining slurry into my new batch of IPA. I probably could have let it sit another 10 minutes to separate out a bit better, but the bottom of the jar was pretty chunky so it worked out good. Had full inoculation within 24 hours of pitching, never seen a batch of beer churn like that before.