Making yeast slants?

[mitch]

Here's a pic of mine.

Looks like some of mine. At this stage I take colonies from a few spots and streak them out on separate plates, in future I might follow Fuse's advice to grow them in a small starter for a bit before streaking.

I'm assuming these individual specks are individual colonies.

Yes but of what? Mould, bacteria, mutant Harveys yeast, wild yeast? You need good growth and separation on a petri dish and a trial fermentation (or a decent microscope).

I'm not sure if you are thinking of lifting something off that slope and growing a starter from it, if you are then please don't. Not only would you probably waste a brew, you could end up culturing 5 gallons of staphylococcus aureus.

[Wolfy]

I'm assuming these individual specks are individual colonies. So, can I use one of these tiny 1mm colonies to kick off 7ml of mini wort?

Possibly, maybe even probably, but like mitch said, colonies of what?
I do not mean to suggest that you've done anything wrong, however I approach making slants and re-culturing yeast from beer/bottles as two completely separate things - rather than mix them together as you've done.

When making a slant I try use a 'pure' yeast source, most often that is a fresh vial, smack pack or commercial slant, yeast colonies on a streak-plate, or yeast from bottle/beer dregs after a starter has been made and tested.
With the purpose of the the slant being to store that yeast strain for later use.

When re-culturing yeast from bottle/beer i prefer to make a starter, so it can be tested via taste and smell as the starter volume is increased.
Since I don't have a microscope I have no way of knowing what is good/bad/other in terms of colonies grown agar (if I did, and if I knew what 'good' and 'bad' yeast looks like, I'd no doubt put it straight onto agar).
However, my theory is that by making a starter with smell/taste tests you can get a fairly good idea if it is fermenting as expected and (hope as a result) that the yeast has out-competed any bacteria or other nasties that may have been introduced from the original beer/bottle sample.
If the tests appear to be OK, only then will the sample be put onto a slant and/or continue building the volume required for pitching. starter to pitching volume.

[floydmeddler]

Here's a pic of mine.

Looks like some of mine. At this stage I take colonies from a few spots and streak them out on separate plates, in future I might follow Fuse's advice to grow them in a small starter for a bit before streaking.

I'm assuming these individual specks are individual colonies.

Yes but of what? Mould, bacteria, mutant Harveys yeast, wild yeast? You need good growth and separation on a petri dish and a trial fermentation (or a decent microscope).

I'm not sure if you are thinking of lifting something off that slope and growing a starter from it, if you are then please don't. Not only would you probably waste a brew, you could end up culturing 5 gallons of staphylococcus aureus.

Was planning on doing just that Mitch but now you've scared me! If you were me, what would you do with this slant?

[floydmeddler]

I'm assuming these individual specks are individual colonies. So, can I use one of these tiny 1mm colonies to kick off 7ml of mini wort?

Possibly, maybe even probably, but like mitch said, colonies of what?
I do not mean to suggest that you've done anything wrong, however I approach making slants and re-culturing yeast from beer/bottles as two completely separate things - rather than mix them together as you've done.

When making a slant I try use a 'pure' yeast source, most often that is a fresh vial, smack pack or commercial slant, yeast colonies on a streak-plate, or yeast from bottle/beer dregs after a starter has been made and tested.
With the purpose of the the slant being to store that yeast strain for later use.

When re-culturing yeast from bottle/beer i prefer to make a starter, so it can be tested via taste and smell as the starter volume is increased.
Since I don't have a microscope I have no way of knowing what is good/bad/other in terms of colonies grown agar (if I did, and if I knew what 'good' and 'bad' yeast looks like, I'd no doubt put it straight onto agar).
However, my theory is that by making a starter with smell/taste tests you can get a fairly good idea if it is fermenting as expected and (hope as a result) that the yeast has out-competed any bacteria or other nasties that may have been introduced from the original beer/bottle sample.
If the tests appear to be OK, only then will the sample be put onto a slant and/or continue building the volume required for pitching. starter to pitching volume.

Cheers Wolfy. Would you agree with this plan then?

Using the yeast that is gathering at the bottom of the beer bottle, create a starter. If this starter tastes good, streak some onto a slant and use to ferment future brews?

Cheers

[mitch]

now you've scared me!

Sorry, I was a bit over the top. I should just have said that you can't assume those white specks are healthy yeast colonies. You need to perform a few more steps to purify and prove the yeast.

If you were me, what would you do with this slant?

1) Plate samples from a few different spots on the slope.
2) Pick some colonies from the plates and store on slope.
3) Do trial fermentations with the sloped yeast.
4) If the trial beers ferment out and flocculate then taste them.
5) Decide which slopes to chuck and which one to keep.

The trial fermentation bit may sound like a ball ache (and it is), but considering the source of this yeast, the conditions it has been exposed to and our lack of microbiology equipment/knowledge/skill, it is the only way to be sure you are getting healthy brewers yeast.

[floydmeddler]

now you've scared me!

Sorry, I was a bit over the top. I should just have said that you can't assume those white specks are healthy yeast colonies. You need to perform a few more steps to purify and prove the yeast.

If you were me, what would you do with this slant?

1) Plate samples from a few different spots on the slope.
2) Pick some colonies from the plates and store on slope.
3) Do trial fermentations with the sloped yeast.
4) If the trial beers ferment out and flocculate then taste them.
5) Decide which slopes to chuck and which one to keep.

The trial fermentation bit may sound like a ball ache (and it is), but considering the source of this yeast, the conditions it has been exposed to and our lack of microbiology equipment/knowledge/skill, it is the only way to be sure you are getting healthy brewers yeast.

Cheers for this. Will be picking up some plates tomorrow at work so will give this a bash. So, just to confirm. I don't need a separate plate for each 'spot'? I can streak a few on one plate if I spread them out?

[mitch]

So, just to confirm. I don't need a separate plate for each 'spot'? I can streak a few on one plate if I spread them out?

I'm sure a skilled microbiologist could do that but I use separate plates for each. If you are feeling lucky then just take two samples and streak on separate plates, I usually do 4.

Could you get a metal loop from work? They are far easier to streak with than needles.

[floydmeddler]

Yep, I can. WIll get 4 petri dishes and a loop. Don't mind that this is a ball ache. Bit of hard work then I can reap the benefits until the day I stop brewing. I'll only have to do this with pints from the pub from time to time. My bank will consist mostly of fresh White Labs yeasts.

You say you streak 4. What is the the typical success rate out of those 4?

Cheers.

[mitch]

What is the the typical success rate out of those 4?

They are usually all OK so I choose based on taste (differences are very subtle and may have nothing to do with the strain of yeast). You do get the occasional one that won't ferment properly or won't settle out even when put in the fridge for a few days. I have had some odd tasting ones as well. I do four because I have four petri dishes not because it is a statistically significant number.

[floydmeddler]

Ah right. Cool. Will have a go at this then. Many thanks for all your advice.

[Fuse]

As both wolfy and mich said "colonies of what" - and as they say you want multiple colonies to pick and run in test ferments to see what they taste and smell like (and obviously separating any bacteria etc) especially from an unknown source like bottes and especially casks.

heres a picture of some plated pure(ish) yeast (appologies taken at work and the lights are not forgiving)


What you can see is a confluent streak at the bottom and then perpendicular streaks to separate out individual colonies, which can then be picked and grown up for testing (as i say done at work so not brewing strains, but you get the idea) im a microbiologist and spend all day looking at and doing stuff like this.

It can be very hard to pick things out from cultures, even under a microscope, without Typing the yeast/nacteria etc - one i looked at recently was Birdmans AG01 as he was having problems with it (shown HERE) and given its smell and taste id have guessed bacterial contamination, but all i could see was yeast cells - so must be wild yeast contamination, so safe to drink but more lambic

[johnmac]

I've just made my first attempt at making slants. One of the 'how to do' websites suggested 2g of agar per 100 ml of wort. That didn't work so I tried 4g/100 ml and had about an 80% success rate. What would be the right amount of agar to use, please?

[floydmeddler]

As both wolfy and mich said "colonies of what" - and as they say you want multiple colonies to pick and run in test ferments to see what they taste and smell like (and obviously separating any bacteria etc) especially from an unknown source like bottes and especially casks.

heres a picture of some plated pure(ish) yeast (appologies taken at work and the lights are not forgiving)


What you can see is a confluent streak at the bottom and then perpendicular streaks to separate out individual colonies, which can then be picked and grown up for testing (as i say done at work so not brewing strains, but you get the idea) im a microbiologist and spend all day looking at and doing stuff like this.

It can be very hard to pick things out from cultures, even under a microscope, without Typing the yeast/nacteria etc - one i looked at recently was Birdmans AG01 as he was having problems with it (shown HERE) and given its smell and taste id have guessed bacterial contamination, but all i could see was yeast cells - so must be wild yeast contamination, so safe to drink but more lambic

Cool. Thanks for this. Mini starters it is then! Be worth it to get this yeast. Amazing flavour.

[Fuse]

I've just made my first attempt at making slants. One of the 'how to do' websites suggested 2g of agar per 100 ml of wort. That didn't work so I tried 4g/100 ml and had about an 80% success rate. What would be the right amount of agar to use, please?

The amount i use is 15g per Litre so the 2g in 100mL should have been fine depends on what your agar source is - check that its 100% pure etc and not mixed with other stuff, as some of them in chinese supermarkets etc can contain a load of other stuff. You need to make sure its all disolved in, are you "autoclaving" it in a pressure cooker or just boiling it up in a pan?

[mitch]

I've just made my first attempt at making slants. One of the 'how to do' websites suggested 2g of agar per 100 ml of wort. That didn't work so I tried 4g/100 ml and had about an 80% success rate. What would be the right amount of agar to use, please?

I use between 1.5 to 2g of Agar Agar powder per 100mL wort, 4g/L sounds quite a lot. In what way are they failing? How are you sterilizing them?