10 month harvested yeast - usable?

[ILMSTMF]

1318 London Ale III
Started, pitched, harvested post fermentation from trub.
Started, over built for harvesting twice more.
Last time harvested was 12-29-16 and I estimated 160b cells. Estimate based on online calculator and ZERO scientific measurement. Hence, estimate.

Ok. I'd like to use this yeast if I can. Conditions for storage have been good. Kept in mason jars under wort and refrigerated.

I realize using harvested yeast within 6 months is ideal. If I build a starter with this yeast, is there any kind of surefire way to verify viability before pitching to wort? All advice appreciated, thanks.

 

[LLBeanJ]

Is there any white yeast left? As cells die, they will turn the color of peanut butter. If there are still some white cells left, they should still be viable.

I've used starter-harvested yeast more than a year later without issue. Begin stepping up a starter and see what happens. Give the resultant starter beer the sniff & taste test and then decide from there.

 

[IslandLizard]

How much slurry is there under the beer? If it's less than 1/2 a cup make a 1.5-2 liter starter with it after decanting the beer from the top.

Homebrew Dad's yeast calculator gives us 10% viability, ~15 billion cells. A 1.5 liter starter should yield around 220 billion cells, give or take.

Let it spin for at least 4 days, possibly longer until you see a precipitate forming. The starter should become much lighter during that time, like a milkshake, which means new active cells.

If the slurry volume is much higher, there's relatively a lot of trub mixed in. After the starter you will still have the same amount of trub plus your old and new yeast cells mixed in. Some saved slurries I had were a thick, light tan colored glue. Used about 1/2 a cup in a 1.6 liter starter and it worked fine.

 

[IslandLizard]

Currently I'm making a starter from almost 2 year old Brett Naardenensis (ECY30), about 125 ml of thin slurry from the original bottle. The starter was dark tan after mixing, and took about 4 days on the (orbital) shaker to become light and milky. I'm letting this go for another 3-4 days, before cold crashing and ramping up again. I really need to start freezing those strains, hard to keep them all in rotation.

 

[Calder]

Last week I used some slurry from March (~8 months). I had planned to use a fresher slurry, but found I had not labeled a couple of yeasts, and it would have been a gamble as to whether I was pitching Thames or Brett-B yeast, so I opted for some that I knew would match the style (Smoked Porter).

I used 2 jars of the slurry (the whole cake - more than I would normally use). I quickly washed the slurry, which probably reduced the viable count by a lot.

Pitched yeast and started to see some signs of life after 24 hours, which is much longer than I am used to I'm sure I under-pitched, but it was alive. I kept temps down to minimize esters from stressing the yeast. I have not taken a sample yet to see how it has done.

 

[ILMSTMF]

Is there any white yeast left? As cells die, they will turn the color of peanut butter. If there are still some white cells left, they should still be viable.
Begin stepping up a starter and see what happens. Give the resultant starter beer the sniff & taste test and then decide from there.

Yep, most of it looks creamy white. Some dark areas but, putting a flashlight on it, it then appears uniform white color.

My problem is I don't have the palate/know-how to determine what to look for in the "experimental" starter. Any time I've done that before, I've found it to smell and taste...yeasty. Beers used with those yeasts have been fine (to me, anyway!)

How much slurry is there under the beer? If it's less than 1/2 a cup make a 1.5-2 liter starter with it after decanting the beer from the top.

Homebrew Dad's yeast calculator gives us 10% viability, ~15 billion cells. A 1.5 liter starter should yield around 220 billion cells, give or take.

Let it spin for at least 4 days, possibly longer until you see a precipitate forming. The starter should become much lighter during that time, like a milkshake, which means new active cells.

If the slurry volume is much higher, there's relatively a lot of trub mixed in. After the starter you will still have the same amount of trub plus your old and new yeast cells mixed in. Some saved slurries I had were a thick, light tan colored glue. Used about 1/2 a cup in a 1.6 liter starter and it worked fine.

This is precisely why I made this post. Wouldn't have thought to stir for 4 days.
The harvesting has happened from fresh starters so, no trub (or very little) to speak of.
I'm using little, half pint mason jars. Don't have in front of me at the moment but there might be a 1/4 inch of slurry on the bottom of each of two jars. That's pretty conservative - might be 1/2 inch. Anyway....

I used 2 jars of the slurry (the whole cake - more than I would normally use). I quickly washed the slurry, which probably reduced the viable count by a lot.

Pitched yeast and started to see some signs of life after 24 hours, which is much longer than I am used to I'm sure I under-pitched, but it was alive. I kept temps down to minimize esters from stressing the yeast. I have not taken a sample yet to see how it has done.

Good stuff.

I suppose I'm hung up on "how much can I start this up to and how much can I successfully harvest for future batches?" I like this strain and I enjoy the practice of harvesting so, would like to keep using for a few more generations. Without some serious science, I don't think I'll have an answer so perhaps best to just start it, harvest, pitch it, see what happens.

Thank you, friends.

 

[LLBeanJ]

My problem is I don't have the palate/know-how to determine what to look for in the "experimental" starter. Any time I've done that before, I've found it to smell and taste...yeasty. Beers used with those yeasts have been fine (to me, anyway!)

Yeasty is fine, to be expected really. What you don't want is excessively sour (a slight sourness is normal, but if it's really pronounced, then you might be tasting a lacto infection), vinegar, or otherwise funky. It should taste like weak, unhopped, beer with no obvious undesirable flavors. If you're going to go ahead and build a starter with it, and I think you should, then make a point to decant and taste once it's done and make a mental note. Then, ferment the beer and if it turns out good, and I'm betting it will, then you have a sort of taste baseline for what starter beer should taste like for making similar evaluations in the future.

 

[ILMSTMF]

Great tips, thank you. Yup, I'm definitely going to start this yeast up and let it rip.
Oh, you know what? That which I've tasted in these tests has been the wort from the starter. Can't bare to dump anything remotely-beer down the drain. So I decant to a cup, decant remainder down drain until I'm left with just slurry. You're suggesting I taste the slurry itself?
PS - drinking that wort leads to a fantastic intestinal distress the next day. lol :smack:

 

[LLBeanJ]

Great tips, thank you. Yup, I'm definitely going to start this yeast up and let it rip.
Oh, you know what? That which I've tasted in these tests has been the wort from the starter. Can't bare to dump anything remotely-beer down the drain. So I decant to a cup, decant remainder down drain until I'm left with just slurry. You're suggesting I taste the slurry itself?
PS - drinking that wort leads to a fantastic intestinal distress the next day. lol :smack:

No, don't taste the slurry. I'm talking about the decanted starter "beer." You'll usually know when something isn't quite right. I had one once that was a bit more sour than I was used to tasting, decided to pitch it anyway and ended up with a sour brew that I had to dump. Another time I had a Hefeweizen strain that tasted a little like hot dog water. Again, I went ahead and pitched it and got 5 gallons of hot dog water beer. Both times I suspected something was off, but rolled the dice and lost. Now, I will dump any yeast that tastes even remotely off. It does takes some tasting and fermenting experience to finally start to get an idea of what is good and what is bad.

 

[ILMSTMF]

DERP. Got it.

I interpreted "hot dog water" as "the water I give to the dog that has been heated" lol

I would like to know what caused those two strains to go bad for you. We can be really careful with sanitation and still get something like this. :shrug:

 

[LLBeanJ]

DERP. Got it.

I interpreted "hot dog water" as "the water I give to the dog that has been heated" lol

I would like to know what caused those two strains to go bad for you. We can be really careful with sanitation and still get something like this. :shrug:

I build up slightly larger than needed starters and save off a little bit of slurry from each one to use for a future starter. The yeast that went sour had been thru at least half a dozen (probably more) of these cycles and must have picked up a bit of lacto somewhere along the line. The other one, now that I think about it, was not a Hefe strain, but actually the Bell's house yeast strain that I got from another forum member who bottle-harvested it from some bottles of Two Hearted or something. I used it the first time without a problem, but the next time I went to use it, it had taken on a bit of a "hammy" flavor. I chalked it up to the bottle harvesting and possible sanitation issues that might have occurred before it came to me.

The moral of the story is that even though you take reasonable precautions for sanitation while handling yeast, the chance of something going wrong is always there, which is why you need to smell/taste that starter "beer" every time to be sure it hasn't picked up something you don't want in your beer.

 

[madscientist451]

My yeast bank has 10-15 strains and sometimes some get kind of old. I'll make a starter and if it kicks off, then brew a small 2-2.5 gallon batch and toss it in to see what happens. If I get off flavors I haven't wasted a whole batch and the slurry from a 2.5 gallon batch makes a nice healthy pitch for a full size batch. So 8 months old is really no big deal, but I don't think I'd go right to a 10 gallon batch with it.

 

[ILMSTMF]

even though you take reasonable precautions for sanitation while handling yeast, the chance of something going wrong is always there, which is why you need to smell/taste that starter "beer" every time to be sure it hasn't picked up something you don't want in your beer.

I'll make a starter and if it kicks off, then brew a small 2-2.5 gallon batch and toss it in to see what happens.

Update - I looked again at the yeast in jars. So damn hard to tell - without a flash light on it, yeah, it does look kind of "peanut buttery" in color. Between both jars, there MIGHT be a combined 1/4 inch of slurry. Whatever. I'm going with LLBeanJ's suggestion. Start it up, taste it and see if it's still good. DME aint that expensive.

Re: small batch... The problem I will always have (my own fault, of course) is that if I'm committing the time to brewing, I must do a full, 5 gallon batch. Your method is 100% smart, no question.

Thank you all.

 

[IslandLizard]

Update - I looked again at the yeast in jars. So damn hard to tell - without a flash light on it, yeah, it does look kind of "peanut buttery" in color. Between both jars, there MIGHT be a combined 1/4 inch of slurry. Whatever. I'm going with LLBeanJ's suggestion. Start it up, taste it and see if it's still good. DME aint that expensive.

Re: small batch... The problem I will always have (my own fault, of course) is that if I'm committing the time to brewing, I must do a full, 5 gallon batch. Your method is 100% smart, no question.

Thank you all.

Yup, good idea. If you have about a 1/4" of yeast cake in the bottom between the 2 pint jars, pour off most or all the beer on top, and add both to your starter vessel. Add some starter wort to the jars if you need to "rinse" the last bits of yeast out. Keep good sanitation!

According to Homebrew Dad's Calc you should get around 220 billion cells from 1.5 liter, perhaps more if you make 2 liter. Although the estimated inoculation rate is a little lower than ideal, at around 7.5-10 million/ml, there's a good chance there may be more viable cells around than estimated. Maybe not. You'll see in the end how thick a layer of yeast you've got after cold crashing.

Count on 2 days on the stir plate, perhaps 4. You'll see the change in color.

When I save yeast from overbuilt starters I decant most of starter beer of the crashed starter vessel, leaving enough behind to be able to swirl it up into a pourable slurry.* It's a bit of a guess, but you'll get good at estimating after a few times. Depending on how many cells I have extra, I then swirl it up and pour some of the slurry into one or two 4 oz mason jars.** The rest will warm up to room temps and pitched into my batch when it's ready, later on.

* Before I decant all the starter beer I pour some of it into a well sanitized pint glass jar, in case I need more starter beer to swirl up or to top off the small jars with saved yeast.

** I often use a scale for that, so I know how many grams (or ml) I save out. I've jotted down all my starter vessels' tare weights, so I know how many net grams (ml) of slurry I have on hand.

 

[ILMSTMF]

If you have about a 1/4" of yeast cake in the bottom between the 2 pint jars, pour off most or all the beer on top, and add both to your starter vessel. Add some starter wort to the jars if you need to "rinse" the last bits of yeast out.

Count on 2 days on the stir plate, perhaps 4. You'll see the change in color.

I decant most of starter beer of the crashed starter vessel, leaving enough behind to be able to swirl it up into a pourable slurry.* I then swirl it up and pour some of the slurry into one or two 4 oz mason jars.** The rest will warm up to room temps and pitched into my batch when it's ready, later on.

* Before I decant all the starter beer I pour some of it into a well sanitized pint glass jar, in case I need more starter beer to swirl up or to top off the small jars with saved yeast.

** I often use a scale for that, so I know how many grams (or ml) I save out. I've jotted down all my starter vessels' tare weights, so I know how many net grams (ml) of slurry I have on hand.

Great tips!

It'll be a 1600ml starter, max. Have danced on thin ice with 2L starter in 2L flask before - that boil over onto stove did NOT please SWMBO...

So yeah, gonna give it a go following this advice. Everybody catch those tips re: saving some starter wort in a separate jar for later rinsing? And keeping notes of tare weights of these vessels? Good stuff, thanks!

 

[IslandLizard]

Great tips!

It'll be a 1600ml starter, max. Have danced on thin ice with 2L starter in 2L flask before - that boil over onto stove did NOT please SWMBO...

So yeah, gonna give it a go following this advice. Everybody catch those tips re: saving some starter wort in a separate jar for later rinsing? And keeping notes of tare weights of these vessels? Good stuff, thanks!

Don't boil in a flask, that's asking for a big mess, and possibly worse, a cracked flask one day.

Just boil your starter wort in a (large enough) clean stainless steel pot (say 1-1.5 gallon), leaving ample headspace. Adding one drop of Fermcap-S will greatly reduce foaming and boil overs. Leave the lid off.

After all the DME has dissolved, boil for 1-2 minutes without the lid. Then turn heat off and put on a clean, well fitting lid. The steam should pasteurize it, or Starsan it for all security. I also wipe the pot's rim with a Starsan soaked washcloth before adding the lid.

I stick the whole pot in a sink or plastic dish washing tub with cold water to speed up cooling, changing the water once or twice. Add an ice pack to the 2nd or 3rd water change, when in a hurry. Just prevent drips and splashes which may contaminate your wort.

When cooled, pour the wort into your clean and well-sanitized flask. I leave mine filled with Starsan until ready for pouring the wort in.

You can note the tare weight on the flask's label with a marker. It does tend to wear off after a while (scrubbing), so touch it up when needed.

1.6 liters is fine, that's what I normally use. When using a stir plate you can fill the flask pretty much to the 2 liter mark. You only need a little vortex. But the use of a drop of Fermcap is essential in that case. I've had a few big krausen foam overs before using Fermcap, always overnight, when no-one is watching.

Note the color change after x days on the stir plate. I'd give it one or 2 days on the stir plate after it turns white (or light).

You should smell the yeast in those storage jars after decanting the starter beer. Or taste some of that starter beer. Those hammy, "hot dog water" flavors and scents are from yeast autolysis. A little is OK, and not detrimental, but if it's really strong, and/or all the yeast looks like peanut butter, I'd buy fresh yeast instead.

 

[ILMSTMF]

Happy to report that this worked! I will try to be brief with details.

1318 wound up being harvested nearly 12 months prior. Built a 1.5L starter and stirred the yeast in it for 4 full days, no crash. 500ml harvested and 1000ml pitched directly to the wort. The estimate was a production of 225b cells from the starter. 135b cells pitched into my low gravity (1.040) pale mild.

The result is FG 1.009 I also harvested from the yeast cake (photos not shown here) into two full pint mason jars. So, have a good stock of 1318 on hand!

The photos show progression starter from day 1 through 3 as well as the "clean" yeast harvested from that starter. Then there are some shots of the carboy as the beer was actively fermenting.

 

[Sbe2]

Happy to report that this worked! I will try to be brief with details.

1318 wound up being harvested nearly 12 months prior. Built a 1.5L starter and stirred the yeast in it for 4 full days, no crash. 500ml harvested and 1000ml pitched directly to the wort. The estimate was a production of 225b cells from the starter. 135b cells pitched into my low gravity (1.040) pale mild.

The result is FG 1.009 I also harvested from the yeast cake (photos not shown here) into two full pint mason jars. So, have a good stock of 1318 on hand!

The photos show progression starter from day 1 through 3 as well as the "clean" yeast harvested from that starter. Then there are some shots of the carboy as the beer was actively fermenting.View attachment 557042View attachment 557043View attachment 557044View attachment 557045View attachment 557046View attachment 557047View attachment 557048View attachment 557049View attachment 557050View attachment 557051

Cool. I tried to resurrect 9 month old 1318 with a starter and after 18 hrs and no krausen it smelled like a dirty diaper. Glad I had some dry yeast on hand.

 

[ILMSTMF]

Glad you mentioned that. The activity was noticed at 30 hours and high krausen occurred at 48 hours. As suggested, I smelled the yeast before pitching to starter. I held back a little bit of the finished starter to taste. In all phases, there were no "off" smells and the bit that I tasted was fine.

Drinking the mild at this very moment and I'm damn happy how everything turned out!