Going To Yeast Slants

[mxd]

Hi All,

I am looking at going to yeast slants and will follow this which I think is identical to a post I read in the forum.

So my questions.

1) How long can a blank slant last ?

2) How long can a inoculated slant last (the article mentions 3 months, I have seen comments about yearly and longer)

3) The article mentions making 500 ml starters, that seems a lot for a small amount of yeast,m so should it start at 250, 500, 1,000 etc..

4) I was looking at getting the test tubes sera is selling (unless I find same at work) is 3 or 4 slants an ok number, or if I think I will use more 1278 then do more 1272 and less 1084

thanks as always

Matt

 

[hockadays]

A blank slant should last quite a while in the fridge. I make up batches of ten and then store at room temp for a week to see if they remain sterile then put it the fride until ready to inoculate. Should last for at least 12 months blank. Personally I have never waited that long. I use about 3-4 per strain of yeast and 3 months is a good time to reculture. If you don't plan on using the strain in that time just make 2 slants per strain. Fill the tube with wort which is about 10ml then go 100ml then 500ml then 2L. I just made some yeasterday in the tubes sera is selling and they work well.

 

[Wolfy]

1) In theory it should last indefinitely. As hockadays suggested I also leave mine at room temp for a few days to a week to see if they grow any infections, if not then store them in the fridge. One thing I have noticed with mine is they do tend to 'dehydrate' over time, that is the agar-mixture shrinks a little and seems to dry out, maybe that's related to how/where I store them or how my fridge works, I'm not sure.

2) Several months is the generally accepted conservative life-span. I tend to work on a 12month life-span for my slants and reculture them each year. On the UK forums someone has suggested that they have reused the same commercially supplied slant (taking just a tiny sample each time) for 4 years now. I guess it depends on how they are stored and the condition(s).

3) I'd suggest using the MrMalty calculator to determine the total size of the starter required (I just treat a stepped-up-slant as a liquid yeast). As for the first steps of the procedure, I base them on the expected quantity of viable yeast being cultured. I have a slant here I'm about to make into a starter, and I plan to start with about 20ml and the yeast from the slant, step up to 100ml, 400ml and then 2L.

4) I guess that most depends on how often you expect to use the yeast within the projected lifetime of the slants you make. For me, I usually make 3 or 4 so slants from each yeast, this allows for losses due to infection, several uses and at least one to repropagate from.

There are no specific wrong or right answers to most of your questions, and I think you'll answer most yourself as you start making/storing/culturing your own slats and yeast, the suggestions above are just what works for me with my procedures and equipment.

 

[mxd]

thanks, will see if I can get some test tubes form work (I have a heated stir plate ready for extraction) on Monday. then get ready to start making blanks.

 

[MattC]

thanks, will see if I can get some test tubes form work (I have a heated stir plate ready for extraction) on Monday. then get ready to start making blanks.

What do you do for a living mxd?

 

[mxd]

I'm a software manager, just work in the biomedical industry.

 

[Thirsty Boy]

I make up half as many "blank" slants as I have available tubes on the day I whip myself into a slant making frenzy.... The other half I fill up with wort. All go into the pressure cooker. The slants get set - the wort provides me with a ready supply of sterile medium to start a step up from, without having to dick around trying to boil and cool less than 50ml to get things kicked off.

I keep mine at room temp for the whole time - here's a photo of slants and wort I prepared in late Feb when I re-cultured my yeast library last. As near as I can tell, they are still pretty much perfect and I would use them without blinking. Next time I re-culture it will take me a lot less time because the slants are already done.



I don't scrape a loop of culture off a slant and then re-seal it when I am building up a pitch.. I just fill the whole slant with wort and then discard the slant. So I make 4 or 5 slants of each strain. Use 4 then re-culture. If it so happens that I am unlucky and the 4th doesn't work out... I will just tough it out and get a new smack pack. Hasn't happened yet and I have re-cultured slants that were 18 months old. I usually only leave it 6 months though.

Thirsty

 

[mxd]

Hi All,

I bought the test tube pack off from Sera (I think) and was planning on making the blanks, now the instructions I have mentions to place the test tube with wort/gelatin mixture in a pot a "steam" it 20 minutes. As my test tubes are rounded bottom, I wasn't too sure if the rack would handle a steam. So was wondering what others have done/used to overcome this issue ?

thanks again.

Matt

 

[Wolfy]

I find agar agar much better and easier to work with than gelatin when making slants, worth the effort if you can get some (most Asian grocery stores stock it).
I have a baby-bottle steam 'sanitiser' thing that has a plastic 'rack' inside (for holding the bottles) that you can also stand the test tubes up in.
When using a large pot as a 'pressure cooker' I put the test tubes and stuff inside a glass (Pyrex) jug, casserole dish or similar.
If you have a small Pyrex jug you might be able to stand all your test tubes up in that, if you are careful when cooling you could also try using a coffee mug or similar.

 

[mxd]

thanks for that, I can jam em in all together so they hold each other up.

I live around the corner from Springvale so no issues about finding Asian groceries.

cheers

Matt

 

[MaltyHops]

thanks for that, I can jam em in all together so they hold each other up.

I live around the corner from Springvale so no issues about finding Asian groceries.

cheers

Matt

Excellent advice all - +++'s ..... one tip that might be useful is to get a really big
syringe for filling test tubes with the agar mix which was pretty messy when I first
started doing this :unsure: . Maybe I've made my slants too thick (tho I followed
the suggested mix amounts) - just fill up the syringe (without needle) with gelatin
nd squirt into the tubes.

T.

 

[Wolfy]

I live around the corner from Springvale so no issues about finding Asian groceries.

The Asian-supermarket on Springvale road (near the pedestrian lights just down from the train station) is where I get mine from.

just fill up the syringe (without needle) with gelatin nd squirt into the tubes.

Yep, good advice, I have a 30ml and 50ml syringe that I use for doing that, it also means you can get the sticky-wort mixture into the bottom of the tubes without mess all along the sides of them.

 

[Banshee]

I dont use slants myself. I purchase petri dishes pre-made from a pathology centre. Been autoclaved and gauranteed sterile. I then get my wyeast smack pack which has been incubating give it an alcohol rub stick a sterile needle in and draw a few mil of and drop it on to the plates. Get some electrical tape and seal the dishes leave them out for a week and then in the fridge. If stored well can last for years.
I scrape yeast of with an inoculating loop which has been flamed into about 80-100ml of wort. I have read that if it has not shown any activity within 48 hours then other mico organisms might beat the yeast and spoil the culture (start again).

I made a starter a week ago and scraped the plate a few times without reflaming the loop and I look at the plate now and see when I rescraped the dish I left a trail of malt on the dish and the yeast has regrown. I will not reuse it even though there is no nasty growths on it as I have plenty in the fridge.

 

[altstart]

I dont use slants myself. I purchase petri dishes pre-made from a pathology centre. Been autoclaved and gauranteed sterile. I then get my wyeast smack pack which has been incubating give it an alcohol rub stick a sterile needle in and draw a few mil of and drop it on to the plates. Get some electrical tape and seal the dishes leave them out for a week and then in the fridge. If stored well can last for years.
I scrape yeast of with an inoculating loop which has been flamed into about 80-100ml of wort. I have read that if it has not shown any activity within 48 hours then other mico organisms might beat the yeast and spoil the culture (start again).

I made a starter a week ago and scraped the plate a few times without reflaming the loop and I look at the plate now and see when I rescraped the dish I left a trail of malt on the dish and the yeast has regrown. I will not reuse it even though there is no nasty growths on it as I have plenty in the fridge.

Hi Banshee
Can I ask where exactly do you buy the Petri dishes and what do they cost.
Cheers Altstart

 

[Banshee]

Hi Banshee
Can I ask where exactly do you buy the Petri dishes and what do they cost.
Cheers Altstart

I'm in Perth and buy them from a local pathology supplier.
I see you are in Qld, I can only suggest to ring around. I buy the cheap plates which cost me about $7.50 for a pack of ten. You can get malt based plates but you only need these if you are putting 100% yeast on them. Like I said above I draw out the yeast slurry from the smack pack which has the goodness in it for the yeast to culture.

 

[mxd]

Hi Guys,

I have made my blanks and am now ready to move on to innooculatin my first slant. I am having trouble finding where to buy ethyl alcohol from (to sterilise the innoculation loop). Where do people buy it or what other methods are used ? Can I just use star-san or a flame on my stove ?

thanks
Matt

 

[MaltyHops]

Hi Guys,

I have made my blanks and am now ready to move on to innooculatin my first slant. I am having trouble finding where to buy ethyl alcohol from (to sterilise the innoculation loop). Where do people buy it or what other methods are used ? Can I just use star-san or a flame on my stove ?

thanks
Matt

Can be tricky getting pure ethyl alcohol - here, need a medical prescription.

Alternatively, I just looked for some vodka with as high an alcohol content as
possible (~40% abv) and put into a tube for this purpose. Seems to work.

T.

 

[Wolfy]

...
I am having trouble finding where to buy ethyl alcohol from (to sterilise the innoculation loop). Where do people buy it or what other methods are used ? Can I just use star-san or a flame on my stove ?

If you have a metal inoculation loop and are working near your gas stove or have a propane/butane lighter/torch just flame it on that.

Unfortunately my inoculation loops are plastic, so store them in StarSan and used some rubbing alcohol until I ran out and cheap vodka the last few times.
I just ordered some 24 SWG NiChrome wire, so when that arrives I'll just sterilise the loop with one of the little propane/butane torches I have here.

 

[mxd]

I will be next to my stove and it is metal so will use my wok burner part and the blue flame.


Thanks all

 

[Banshee]

isopropyl alcohol.

If you look at the alcohol wipes that they use on the skin prior to injections you'll see it is 70% isopropyl alcohol and 30% water.
You can buy isopropyl alcohol in a tin from your electronics supplies (Alltronics) and mix some with boiled, cooled water at ratio of 7:3.
The reason that you dont use 100% is it can shock the bugs and they put up a safety barrier where as a 7:3 mix kills them.