Slanting yeast

Williams 728
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Hello everyone,

Please forgive me for not having read all pages if this has been corrected, but in the first page it is mentioned that the pressure cooker should be run at a pressure of 12psi. This is less than 1 bar ==> technically impossible unless we'd be using a depression chamber, not a pressure cooker.

Or maybe this is a specificity of pressure cookers in the US, do they maybe show the additional pressure on top of the atmospheric one? (12psi would mean 14.5 psi (1 bar) + 12 psi)?

Anyone can help clarifying this?

Thanks!
 
Elkaybay said:
Or maybe this is a specificity of pressure cookers in the US, do they maybe show the additional pressure on top of the atmospheric one? (12psi would mean 14.5 psi (1 bar) + 12 psi)?
Click to expand...

Yes, the 15psi is in addition to the atmospheric pressure (so it maintains a 15 psi difference from atmospheric pressure). I am not familiar with pressure cookers outside of the United States but I would have expected all pressure cookers to work this way.

Edited to add: browsing around Amazon.co.uk and it's clear that the same is true in the UK as well. Pressures indicated are gauge pressures (difference with atmospheric pressure). In a site discussing safety reguations for pressure cooking it points out that the EU rates pressure cooker pressure in bars, which is by definition a gauge pressure. So you now you have me curious! Have you seen a pressure cooker which indicates pressure as an absolute pressure?
 
My pressure cooker simply doesn't have a gauge :)

Thanks for the explanation! I already see a flaw with these differential valves, your pressure cooker won't work the same at sea level and at a 3000m altitude, when indicating 12 psi in both situations :)

Enough off topic. I'll start slanting my yeast next week! I hope I don't contaminate anything. Thank you very much for the wonderful introduction!
 
I'm at 7000'

If you figure it out I'm supposed to hit 18psi for 15 minutes but I'm always wary of too much pressure. If the media I'm sterilizing can handle it without too mich degradation (agar or pH issues, off the top of my head) you can do the lower 15psi just for 30 min.
 
Hello all,



I have been slanting yeast for a couple months now, and earlier today I came across an article about storing yeast in sterile Distilled water versus on a slant. The benefit being the ability to store for much longer periods of time without refrigeration. The thought being that the yeast just go dormant having to food source- ergo, not mutating.



Does anyone use this method? Any other thoughts?
 
I personally think storing in sterile water is inferior to slanting which is inferior to freezing at - 80.

You have to pick the method you can afford and the technical level you're comfortable with.

Eureka Brewing's blog has a nice writeup on sterile isotonic saline yeast storage. Just google for it.

If you're already slanting (successfully), going with water storage is a step back... in my (and many others) opinions.
 
So I'm just starting to get back to brewing after a couple years away and my slant library is pretty neglected. I'll just toss the common stuff like wlp001 and start over, but I have some slants that id prefer not to lose like harvested Conan and Bells.

The slants are looking a bit ragged and don't have that super nice white creamy look anymore.

I was thinking about plating out from these slants in an attempt to grow a new colony to reslant from, but looking at them are they too far gone?

View attachment ImageUploadedByHome Brew1450761533.757487.jpg
 
You could culture up a bunch of strains with a lot of drift/mutations. Not a good idea for your mother culture.

I'm not saying it's all dead, I'm saying you don't want that yeast.

You could run trial fermentations on all of the strains to see if attenuation, floculation, flavor compounds and what not are where they should be.... but that's a lot of work. I'd just rebuy or trade to replenish my stocks.... but time to me is more valuable than a 7$ smack pack.

You might be able to craft a deal with a local homebrew owner and buy his culled packets of yeast for a discount. There may be viability issues in a 6 mo old smack pack but that's an issue for brewing, not isolation and slanting. There should be minimal genetic drift and plenty alive in 6mo if the packs were stored properly.
 
butterpants said:
You could run trial fermentations on all of the strains to see if attenuation, floculation, flavor compounds and what not are where they should be.... but that's a lot of work. I'd just rebuy or trade to replenish my stocks.... but time to me is more valuable than a 7$ smack pack.
Click to expand...


For the bottle cultures it's worth a shot and doesn't take that much time to do it. Presumably he'll be making new plates anyway so just make a few extra and then a master batch of starter wort and see how the yeast off the plates perform in the real world.

I agree on the standard strains that just getting fresh yeast is better than reslanting the old stuff.
 
Gentlemen, a quick question:
I by mistake sterilized a ton of vials for slants with 1030 gravity wort instead of 1040 as generally recommended. I hate the idea of redoing the whole thing.
So, will it do - or will it be too risky as the yeast might not have enough nutrition?

Thanks everyone :)
 
Does the stirring action affect the way 100~500ml starters look and behave?
------------------------------------------------------------------------------------
any one using WL036 from a slant to make a starter?

I am a newbi at slant to starter propagations...
The yeast is certainly increasing in number as there is a nice white layer of new yeast after cold crashing.... but, 036 is supposed to be a top cropping yeast... I am using a very gentle stir plate that keeps the surface slightly moving, and I got a finger thick layer of bubbles between say 12 and 24 hrs, but then it went away.

Very few and infrequent bubbles could be seen rising to the surface, but for the most part, it seemed to be inactive.

It is hard for me to form a good question... help?
humm, what does a top fermenting yeast look like when going from slant to say 500 ml?

Will a top yeast cake form even with stir plate action,
or will it look the same as a lager yeast propagation?

Is the yeast bubble head cake I observed for a few hours under stir plate activity, karausen, or just foamy wort bubbles?

I did an 830 prop at the same time, and its bubbles were much more "normal fermentation" like... (i.e. vigerous), but the 036 was stelth-like, producing lots of cells but not so many obvious tell-tale bubbles.

Anyone have a picture of your 036 starters starting up?
 
I don't think there's a strong correlation between lack of a kreusen in a starter and it not producing in log phase....

Some starters seem to get super foamy, some not.

When I think angry top croppers, my mind goes to 3787. That god damm yeast will fill 5 gallons of head space in a 10 gallon fermenter in 3 days.

That said, its starters always show lots of activity for me..... virtually any volume.

Apples to oranges but a perspective.
 
GQT said:
Gentlemen, a quick question:
I by mistake sterilized a ton of vials for slants with 1030 gravity wort instead of 1040 as generally recommended. I hate the idea of redoing the whole thing.
So, will it do - or will it be too risky as the yeast might not have enough nutrition?

Thanks everyone :)
Click to expand...

1.030 will do. Mr. Malty says that starter wort should be between 1.030 and 1.040... So 1.030 for your slants should work.

http://www.mrmalty.com/starter_faq.php
 
Be leave it or not I did some slanting 2 years ago... I moved and got ride of most of my washed yeast. I used 3 vials to make a new started... it's still alive.. so I'm gonna get rid of my slants and start again
 
A question out of mere curiosity, what is your favorite slant size?
20 ml tubes I normally use are to my taste a bit too long and I don't feel comfy inoculating them with the long and too flexy loop.
10 ml size would be ideal to my feeling but will that mean I'm not giving enough food to the yeast? (a slant in a 10 ml tube will hardly have anything more that 2-3 ml wort).
I'm soon going to order a new pack of tubes, so need to decide the size.
Thanks everyone!
 
Cynmar sells 85mmx25mm (ish, I could be a little off) borosilicate glass with resin autoclaveable caps. That's all I use. Love um
 
butterpants said:
Media is cheap.
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Nice incubator. I made mine using a lunchbox/beer cooler with a copper coil running along the walls. Water runs through coil and aquarium cooler/heater.

Nah, I don't mean agar is expensive or anything alike. Just want to use smaller tubes.

Some say as little as 3 ml media would be enough, I just wanted to see if others had good results with this amount. If yes it will solve my problem alright.
I live in a flat, not house. Small kitchen, limited fridge volume, all that.
 
There are little 5ml macro centrifuge tubes with screw tops. If you're so short on space, might as well try it
 
I have a lot of aging pilsner malt that might not be as tasty as fresher stuff; but think it should be more than ok for slanting and propagation use. :)

Elementary, Watson, to be sure, but what would be a suitable mash schedule / procedure?

I get that a tripple decoction is unnecessary, but how would YOU do it?

I plan on canning it for later use.
 
mash 158 for 15 minutes, lauter and dilute to 1.030

add 2% w/v lab grade agar, some DAP/yeast nutrient if you're feeling sassy..... autoclave, sterilize, whatever you do.

cool to 115F or so and pour into pre sterilized slant tubes.

FYI, I would never mash a batch just to make slants/plates.... DME is just too cheap to go through all that cleanup and hassle for me.
 
I have notice that the coverslips that come with the chinese hemocytometers may varry in size.. 22x22, 20x22, 26x22 as well as perhaps in thickness, and so I was wondering what is the OK range;

What size coverslips are suitable for use with these hemocytometers?


Butterpants -
Thanks. Yes, I know. I just have an excess of malted grain and some time on my hands.
 
GQT said:
Why would anyone suddenly want antibiotics in his slants?
Click to expand...

Standard antibiotics can be used, provided you can legally acquire them, to inhibit bacterial contamination without otherwise inhibiting the desired yeast.

With proper aseptic transfer techniques they're not necessary, but if you have the resources to use them there's no reason you couldn't.
 
You can buy SDA+ chloramphenicol on amazon and white labs sells cyclohexamide
 
I recently started making slants and my culture tubes are boiling over and I'm loosing some media.

Using 20x150mm (30ml) tubes. I fill 1/2 with media, put them in a rack. Lids are on loose. Place in the canner and fill with water to about 1/2 way up tubes. Start stove, close lid. Once steam starts to vent from the top hole I set the timer for 10 min. Then add 15lb weight. Once it starts to vent I turn down the heat and let it do it's thing for 15 min. Then I turn off heat and wait for the the pressure valve to release. I don't move the pot or cool with water. Just let it sit for 30-45 min. Then I open the lid and there is always some media boiled over in the water.

Am I doing anything wrong? Is this normal? Thanks.
 
As the pressure releases, the boiling point changes and if the solution hasn't cooled down enough, it'll boil. That's one reason why you only fill containers half full when autoclaving. Also there are tons of nucleation sites for a boil to take off if there's some type of break material or undissolved agar in there.

I do it by autoclaving the tubes separately (or buying pre-gamma irradiated ones) from the media. Get a cheap media bottle from Cynmar. Then let it cool to like 110F and pour into the tubes in a sterile manner. Way less mess this way.
 
butterpants said:
As the pressure releases, the boiling point changes and if the solution hasn't cooled down enough, it'll boil. That's one reason why you only fill containers half full when autoclaving. Also there are tons of nucleation sites for a boil to take off if there's some type of break material or undissolved agar in there.

I do it by autoclaving the tubes separately (or buying pre-gamma irradiated ones) from the media. Get a cheap media bottle from Cynmar. Then let it cool to like 110F and pour into the tubes in a sterile manner. Way less mess this way.
Click to expand...

It's just funny that no one really talks about boil overs with their culture tubes so I figured I was doing it wrong. Doing what you do may be the best way to go. Kinda like pouring plates.
 
jwalkermed said:
It's just funny that no one really talks about boil overs with their culture tubes so I figured I was doing it wrong. Doing what you do may be the best way to go. Kinda like pouring plates.
Click to expand...

This is more common a problem I believe using a pressure cooker style of sterilization vs a truly automated autoclave. Pressure releases too quickly.

When I make LAB broth to propigate bugs for a big kettle sour pitch (glucose, dme, dap and calcium carbonate) it always boils over making a mess.... even 1L in a 2L media bottle. Annoying but it's very easy to clean up.
 
Another issue I ran into. I grew yeast on my slants. After about 1 week I poured sterile water to store in the fridge. A lot of the yeast has fallen off the slant and settled in the liquid. Anyone else have this issue?
 

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