Slanting yeast

I went shopping for pressure cookers today and the ones made here have just one pressure setting, 80 kPa, which seems to translate to 11.6 psi. Would this work ok? Maybe if give the items i'm sterilizing a few more minutes of steam time?

Again, I'm filing a request forwarded to the honorable members of this gentelmen's forum.

Is anyone willing to help me in buying the glass vials for me? I shall pay upfront vials+shipment.

Thank you.

LovesIPA said:

Attached are two pictures of the first starter that I made using a yeast slant. I've made roughly a dozen starters in the past, often right from a White Labs vial. I've heard people talk about pitching starters at high krausen but I've never actually had a lot of krausen on a starter. A few bubbles, maybe some traces of foam but that's it. I use fermcap so I figured that must be it.

NEVER have I seen this much krausen on a starter before. If you're even thinking about making yeast slanting next on your homebrewing adventures, I highly recommend it.

The first picture is yesterday, about 5 hours after I pitched the yeast from the 250ml starter into the 1.1L starter. The second picture is when I got up this morning.

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For how long have you let the 250 ml starter sit, before pitching it in the 1 L starter?

Ty

kukubau said:

For how long have you let the 250 ml starter sit, before pitching it in the 1 L starter?

Ty

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I usually pull it off the stirplate and pitch it right into the larger flask, spent wort and all. It gets decanted later so I don't see the point of going through the cold crash/decant cycle more than once.

Purchased a pressure cooker. I'm wondering if it's ok to use it for cooking as well, or will that foul it up?

Do you guys think commonly used dry yeasts like S-04 and US-05 are worth slanting, or do you prefer to just buy fresh packs for each batch. Wondering whether it is worthwhile when you factor in the costs of DME etc.

I always steal a few cells out of the rehydrating yeast and make a few slants with it.

The cost of making starters is trivial compared to actually buying yeast, even when you factor in the DME.

Those are major strains, so it depends on if you want to use them a lot. I only use them once or twice a year, so I just get a new packet and make a starter. If it were my primary, then I would say slant it for sure.

I ordered all the gear to to this, and it should arrive Tuesday. In the meantime I got some disposable petri dishes and made the agar medium. I made a couple batches of beer, so I smeared some of the yeast onto petri dishes hoping to make slants with it later.

Problem is, in the plating tutorial in the site, it shows that you should have single cell colonies to use to make slants. I must have smeared to much though, because what I am growing is thick white lines of yeast, with no individual dots.

Can I use this when I get the vials, and if so, how?

It is not necessary to first inoculate on Petri dishes. You can go ahead with the tube slants.

kukubau said:

It is not necessary to first inoculate on Petri dishes. You can go ahead with the tube slants.

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I didn't have the slants yet, so I used the petri dishes as a temporary solution. Problem is, I spread it on a little too thick I think, so there are no single cell colonies, just long thick smears. Can I go ahead and transfer that to slants anyway?

Hello again. I followed the directions implicitly. After 36 hours I have one slant that is solid, and the rest are still liquid wort. Some of the slants have a thin gelatin layer at the very bottom, but are completely liquid thereafter. In section 3 it's stated that the amount of agar agar is 2.5 grams to the 35 grams of dme, and that is precisely what I used. The agar agar I found is in powdered form. What did I do wrong? Did I not mix it enough, and if so, why didn't the time in the pressure cooker mix it? I'm a little bit let down over this! Thanks!!!

Did you heat the wort and agar mixture up and stir it before pouring it into the vials?

I skipped that part the first time I did this, thinking it wouldn't make a difference, and that's what happened to me. If you follow the instructions you will end up with slants. I do every time!

NaymzJaymz said:

Hello again. I followed the directions implicitly. After 36 hours I have one slant that is solid, and the rest are still liquid wort. Some of the slants have a thin gelatin layer at the very bottom, but are completely liquid thereafter. In section 3 it's stated that the amount of agar agar is 2.5 grams to the 35 grams of dme, and that is precisely what I used. The agar agar I found is in powdered form. What did I do wrong? Did I not mix it enough, and if so, why didn't the time in the pressure cooker mix it? I'm a little bit let down over this! Thanks!!!

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That exact thing happened to me that first time. The agar powder doesn't dissolve as easily as the DME, so be sure to boil it until it is fully dissolved. It's hard to tell for sure, but my second try came out perfect.

dave8274 said:

I didn't have the slants yet, so I used the petri dishes as a temporary solution. Problem is, I spread it on a little too thick I think, so there are no single cell colonies, just long thick smears. Can I go ahead and transfer that to slants anyway?

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Go ahead and transfer !

Thanks guys, that may very well be what happened. The directions say that boiling isn't really necessary, so I heated it up and mixed it well(I thought). I'll try it again.

NaymzJaymz said:

Hello again. I followed the directions implicitly. After 36 hours I have one slant that is solid, and the rest are still liquid wort. Some of the slants have a thin gelatin layer at the very bottom, but are completely liquid thereafter. In section 3 it's stated that the amount of agar agar is 2.5 grams to the 35 grams of dme, and that is precisely what I used. The agar agar I found is in powdered form. What did I do wrong? Did I not mix it enough, and if so, why didn't the time in the pressure cooker mix it? I'm a little bit let down over this! Thanks!!!

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I have the same problem. I followed the directions with Agar from the asian market. I even heated it to boiling to make sure it was well dissolved. Let the slants rest for a long time, and now when I pick them up they just fall to the bottom of the vial. I wonder if I just need to up the amount of agar.

I just tried it again with a very slight increase in the agar. The directions say "about 2.5 grams" so a little more shouldn't hurt. This time I boiled the mixture and cooled it enough to safely fill the vials. Now I appear to have the exact opposite "problem". The mixture started to set as soon as I poured it into the vials, and again after removal from the pressure cooker. I got them taped and into the slant position just in time! Is there any way that this will affect their potency? I think DWhitwell was right in that I should've mixed better the first time. One question that comes to mind, why does it take so long for a concentrated amount (a drop)of yeast placed on the host to incubate? If it was pitched into wort it would be much quicker, right? Is there any way or any reason to "test" one of these slants? How about with a few drops of common yeast, or would that be a waste? Thanks again.

I got a few slants going Wednesday night when I made a starter of some Pacman yeast. They were a little mushy, the next batch of slants I made worked better with more agar agar in them.

I'm brewing another beer in a couple days which calls for US-05 so I figured I would try out a starter with my Pacman even though it's only been 4 days since I made the slant, and if it didn't work I could always go get a pack of US-05 this week.

There was some white yeast growing on the slant, so I followed the directions and put some wort in the vial, shook it, and funneled it into the flask. It seemed to work ok, but I did get a few chunks of gelled agar in the flask. Is this going to create a problem? The agar is bright green and though there are only a few small chunks, I don't want them to eventually end up in the beer. Is there a safe way of fishing them out, or am I better off just leaving them?

I would leave it. It's almost undoubtedly fine to pitch and it almost undoubtedly will settle out in primary.

NaymzJaymz said:

I think DWhitwell was right in that I should've mixed better the first time.

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Holy crap, how did that happen?!? I never get it right! I guess even a blind squirrel finds a nut once in a while... :cross:

Seriously, though, mine did come out much better the second time, when I made sure I mixed the agar in thoroughly, by boiling and stirring. I'll be innoculating my first slants next Wednesday, wish me luck.

As to why it takes so long for the yeast to propagate on the slant, I'm sure it has to do with the small amount of yeast you're starting with.

DWhitwell said:

Holy crap, how did that happen?!? I never get it right! I guess even a blind squirrel finds a nut once in a while... :cross: Seriously, though, mine did come out much better the second time, when I made sure I mixed the agar in thoroughly, by boiling and stirring. I'll be innoculating my first slants next Wednesday, wish me luck. As to why it takes so long for the yeast to propagate on the slant, I'm sure it has to do with the small amount of yeast you're starting with.

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It is also a much more dense medium than the wort we get after a boil.

Okay here's a new thought. In the original article we are instructed to put the solidified slants in a ziplock bag and keep them in the closet. Would it be better or worse to keep them in the refrigerator?

They're completely sterile, so I don't really think it matter where they are kept as long as airborne contaminants can't enter the vial. I actually forgot the OP said that. Mine are sitting at room temperature still in the cardboard box I used to create the slant.

Here are my 1st couple of slants. The yeast looks nice and white, but for some reason my slants are accumulating fluid at the bottom of the vials. Even the newer ones I have made with more agar are doing this. When putting the yeast in the vial, I poured out any liquid that had accumulated by condensation, so I'm not sure what is going on and whether it's a problem.

Aside from the color they look fine. Why are they green? The should be dark tan.

LovesIPA said:

Aside from the color they look fine. Why are they green? The should be dark tan.

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Heh the Agar at my local Asian gricery is bright green, but it's just food dye.

dave8274 said:

Here are my 1st couple of slants. The yeast looks nice and white, but for some reason my slants are accumulating fluid at the bottom of the vials. Even the newer ones I have made with more agar are doing this. When putting the yeast in the vial, I poured out any liquid that had accumulated by condensation, so I'm not sure what is going on and whether it's a problem.

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Mine also accumulate fluid at the bottom of the slant. It won't affect anything. Occasionally Ill pour the excess fluid out of the vial when inoculating. I normally just leave it in there. The yeast grows in the fluid just fine.

I've been holding off on sharing my results so far, because I haven't grown up a starter from a slant and made a beer yet, and, to me, that is where the proof really is. But, here's what I found so far:

I found powdered white agar at an asian market. I found 24ml vials with autoclavable lids at cynmar.com, and got an alcohol lamp and loop as well. I use mason jars instead of beakers. The first batch of agar did not set due to not being mixed well enough - boiling DID seem to be needed. Using a mop handle gave me a good angle on the slant. I used a gauge-less pressure cooker, but the manufacturers manual said it achieved 15 pounds of pressure. When I slanted, I found, like many, a little liquid - maybe condensate - and just dribbled it out before I slanted. I slanted both liquid and dry yeast, both seemed to grow adequately. My slants did not show signs of other growth, and did not push the agar out of the vial like others have found. I did use the loop to push yeast into the agar, but not all the way through to the glass side of the vial. They are now taped up and in the fridge. I plan to "waste" one just to make sure it can be stepped up adequately, but since I'm not doing a yeast cell count, I won't know for sure - I'll just compare it to my experience based on appearance of yeast when I chill and decant before pitching.

Thanks to all of you who have contributed so much to this thread, especially the OP. I like the idea of maintaining a yeast bank as well as saving a little $ in the long run. I'm also especially excited about this because I'm putting together a 1 gallon AG test batch system, and love the idea of having more yeast to play with!

Oh, and for alcohol for the lamp, denatured alcohol paint stripper from the big box hardware store worked great!

Okay, so I was just looking at my slants. I have one amendment and a recommendation. When I sealed up the yeast, I saw a couple of fruit flies in the bottom of the jar holding the slants (with the jar covered with sanitized foil). Clearly, on that jar, the flies were able to get into the slant. I recommend perhaps a sanitized nylon stocking over the jar, with the foil over that...

DWhitwell said:

Oh, and for alcohol for the lamp, denatured alcohol paint stripper from the big box hardware store worked great!

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I use fondue pot oil from the Dollar Store.

If you are going to re slant from your last remaining slant, how many generations is it ok to do this for, before you need to start with a new fresh package of yeast?

dave8274 said:

If you are going to re slant from your last remaining slant, how many generations is it ok to do this for, before you need to start with a new fresh package of yeast?

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That's a question of great debate. Some people will say up to 10 generations. Some yeasts are more sensitive to mutation (the Conan strain from the alchemist is rumored to be very, very sensitive). What's the strain? Some people may have first hand experience with it.

dave8274 said:

If you are going to re slant from your last remaining slant, how many generations is it ok to do this for, before you need to start with a new fresh package of yeast?

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Why wouldn't you just use the last slant to make a starter? Once the starter is ready, plate it out and isolate a single colony for each new slant...

BoShimTang said:

Why wouldn't you just use the last slant to make a starter? Once the starter is ready, plate it out and isolate a single colony for each new slant...

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I might be wrong, but I think that's what the poster meant: How many generations can you use your last slant to make a starter AND some new slants? Each time you did this would technically be a new generation.

BoShimTang said:

Why wouldn't you just use the last slant to make a starter? Once the starter is ready, plate it out and isolate a single colony for each new slant...

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I could do that. I was planning to take the sample from the slant before making the starter, but after works fine. I tried plating once though, and had no success getting an isolated colony. Might have to try it again. Is there anything wrong with just taking a bunch from the slant without isolating a colony? That's what the original post suggests doing.

dave8274 said:

I could do that. I was planning to take the sample from the slant before making the starter, but after works fine. I tried plating once though, and had no success getting an isolated colony. Might have to try it again. Is there anything wrong with just taking a bunch from the slant without isolating a colony? That's what the original post suggests doing.

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Isolating single colonies helps avoid contamination. Buy an inoculating loop and either an alcohol lamp or a propane torch and read up on plating technique. It takes practice but it is really simple once you figure it out.

Pierre Rajotte's book "First Steps in Yeast Culture" is an excellent resource as is Chris White's book "Yeast."

BoShimTang said:

Isolating single colonies helps avoid contamination. Buy an inoculating loop and either an alcohol lamp or a propane torch and read up on plating technique. It takes practice but it is really simple once you figure it out.

Pierre Rajotte's book "First Steps in Yeast Culture" is an excellent resource as is Chris White's book "Yeast."

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I do have the loop and the alcohol lamp. I just figured the plating step in between would increase the chances of contamination vs just going straight to the slant.

dave8274 said:

I do have the loop and the alcohol lamp. I just figured the plating step in between would increase the chances of contamination vs just going straight to the slant.

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Sterile technique is critical. Of the two books I listed, I most highly recommend Rajotte's as it is thorough but brief. Assuming you also have access to a pressure cooker with a gauge, you should have no problem with contamination. The selection of an isolated colony ensures that you have a pure culture derived from a single cell.