Slanting yeast

[butterpants]

Cynmar sells 85mmx25mm (ish, I could be a little off) borosilicate glass with resin autoclaveable caps. That's all I use. Love um

 

[GQT]

85mmx25mm

That's 40+ ml, might be an overkill and waste of media, huhh?
What do you think is a minimally sufficient volume of wort+agar to support the slant for a few months' hibernation in the fridge?

 

[butterpants]

You're only filling it halfway for slants.

Media is cheap.

Really large surface area for lawn growth.

I'm not sure how low you could go. If sealed properly, pretty low.

View attachment 1452181988500.jpg

 

[GQT]

Media is cheap.

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.

 

[butterpants]

There are little 5ml macro centrifuge tubes with screw tops. If you're so short on space, might as well try it

 

[JawZziff]

wow! I f***ing love science!

 

[Blue-Frog]

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.

 

[butterpants]

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.

 

[Blue-Frog]

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.

 

[defrandj1]

Does anyone use an antibiotic in their slants? If so, which one and how much?

 

[GQT]

antibiotic in slants?

Why would anyone suddenly want antibiotics in his slants?

 

[BugHunter]

Why would anyone suddenly want antibiotics in his slants?

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.

 

[butterpants]

You can buy SDA+ chloramphenicol on amazon and white labs sells cyclohexamide

 

[jwalkermed]

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.

 

[butterpants]

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.

 

[hottpeper13]

Why would anyone suddenly want antibiotics in his slants?

Antibiotics I thought were used in PLATING agar now called WMD and that kills the yeast so we can look for contamination.

 

[jwalkermed]

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.

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.

 

[butterpants]

antibiotics i thought were used in plating agar now called wmd and that kills the yeast so we can look for contamination.

he's got a bomb, lookout!

 

[butterpants]

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.

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.

 

[jwalkermed]

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?

 

[butterpants]

I don't use water to top um

 

[ba-brewer]

My recipe for slant media is:

1.5% agar powder
7% DME
1% Wyeast yeast nutrient

That is by weight so if you have, say, 500mL of water you will add 7.5 grams of agar and 35 grams of DME along with 5 grams of the nutrient.

The agar powder def. works better than the stuff I got at the grocery store, which after a few months in the fridge started falling apart.

The wyeast nutrient I have calls out 2.2grams for a 5gal batch, did they change their formula since this post? If you really need this amount what is the reason?

 

[ba-brewer]

The beginning of this thread calls out using a whole slant in 250mL of starter as the first step, but toward the end it seems like people are just using a few loop of yeast in a 10mL as the first step. What is the current thoughts on this?

I like the original approach as it has less steps, but it seems like if you start with a 10mL step you could reduce the number of vial of yeast you need to have hand for any given strain.

 

[Blue-Frog]

Hi everyone; Recently I have been 2nd guessing the strength of my slants & plates.... it seems there is a range of gravities being used, anywhere from 1.002 to 1.040 and so my question is what strength are you using and why, or perhaps better, whose suggestion are you following?

 

[ba-brewer]

Hi everyone; Recently I have been 2nd guessing the strength of my slants & plates.... it seems there is a range of gravities being used, anywhere from 1.002 to 1.040 and so my question is what strength are you using and why, or perhaps better, whose suggestion are you following?

I use the information from this post early in this thread.

My recipe for slant media is:

1.5% agar powder
7% DME
1% Wyeast yeast nutrient

That is by weight so if you have, say, 500mL of water you will add 7.5 grams of agar and 35 grams of DME along with 5 grams of the nutrient.

The agar powder def. works better than the stuff I got at the grocery store, which after a few months in the fridge started falling apart.

​

I reduced the amount of nutrient from 5 grams down to 1 gram. I was initially nervous about the amount of nutrient as it seemed like a lot compared to what you use in a 5gal batch but after looking thru the information on the maltose falcons yeast page the amount makes sense but it looks like more nutrient just speeds up the growth process but does not increase the total number so I went with less. So far most of my slants have filled in nicely within 4 or 5 days.

 

[Blue-Frog]

I could't find out how much DME/SG they (Maltose Falcons) sugg. for slants & plates, perhaps in my haste I overlooked it?

 

[ba-brewer]

I could't find out how much DME/SG they (Maltose Falcons) sugg. for slants & plates, perhaps in my haste I overlooked it?

Look at the text right above table 1, it suggests using the same wort strength as a starter, table 3.

 

[Blue-Frog]

Look at the text right above table 1, it suggests using the same wort strength as a starter, table 3.

ba-brewer, thanks. I got it.
In the sprit of "One good deed deserves another" I would point out that the author is actually saying in effect, NOT to use starter strength media for propagations.

At least that is how I read it.

Thanks again.

 

[ba-brewer]

I went back and reread the paragraph and it does seem like that they are recommending to make slants from a low gravity medium.

I looked closer at table 3 and the recommended recipe(1.5%agar, 7% DME, 1%nutrient, 91% water) in this thread and it looks like the wort strength in this thread would be less than 1040 but higher than table 2.

I also look at the "Yeast" book and it says for slants/plates use 1040 wort and an unspecified amount of nutrient then boil to form hot break so that should give something more than 1040.

Seems like most things in brewing in that there is plenty of leeway in how you do things and still get acceptable results.

 

[kmarkstevens]

Not sure how to tag this thread, therefore replying here so I can track it when I have time to wade thru all these posts.