Yeasty's Yeast Slants (slopes)

Post #26 made 12 years ago
How that go yeasty?? Not sure if I'll use mine, appears to have very poor flocculation. Did second step up for about 36 hrs then several days in fridge. Liquid very cloudy/yeasty and FG at 1.012. I have the Chris White and Jamil book which I'm only starting to read but they've a detailed procedure for freezing that's a bit more involved than anything online. I don't brew often enough to screw up a batch and a guy in work has offered me some saved yeast. Not sure what to do ......

L

Post #27 made 12 years ago
Hi Lars

I've not got round to innoculating my slants yet, I've some saved yeast and some recovered Bluebird yeast in the fridge I've just got to find the time :idiot:

Back home tonight from my weekend jolly so hopefully I'll get round to it this week.

The saved yeast should be OK as long as you are sure its been treated correctly, I'd make a starter with it and check it before commiting it to a brew.
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Post #28 made 12 years ago
I finally innoculated some slants last Friday :party: the prepared slants have sat under my desk for over 6 weeks which was a good thing as I have had a few failures. Not the medium but around the cap. I think this is because I had a bit of condensation in the tubes and this had run under the threads of the caps. Being slightly sweet from the medium it allowed mold to grow.
None were contaminated inside the tube but I had to ditch them as it would have been impossible to clean off, innoculate and be sure they were still sterile.

The 3 I innoculated have colonised wwell and will now go in the fridge.. :thumbs: I'm going to wash some yeast off my APA and make some more and possibly look into freezing.

Note: Pics to follow.
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Post #30 made 12 years ago
Has anyone successfully dried yeast ? or heard of any one who has done it ? I think I have read about it somewhere :scratch: not sure if it was dried or just still damp/wet.

My idea it to try drying it under a vacuum. I can set up a vacuum pump to remove air from a space containing a yeast sample, at low pressures the water will evaporate at room temperature effectively drying the yeast. :think: Perhaps a test tube containing the yeasty inside a vacuum chamber ? perhaps with a one way valve so as to not let any air back in once the vacuum is released ??
I think I'll research it further and have a good think about it, feel free to pick holes in my idea :shoot: :shoot: the main point is will the yeast survive drying under a vacuum, I'm sure that how the big boys do it.

EDIT: I need one of these babies Here
Last edited by Yeasty on 18 May 2012, 17:34, edited 3 times in total.
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Post #31 made 12 years ago
Yeasty, I have in the past, chilled the yeast to freezing(not on purpose), and forgot about the bag of frozen slush, for 2 months...

When I warmed them up, they came alive at the 20C range and worked well to make some Good Beer!!

My point is you may want to try, "Freeze drying" Vacuum pump the water from the Ice!!!
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Post #32 made 12 years ago
Yeasty wrote: EDIT: I need one of these babies Here
Weight net 12,000 to 35,000 kg

The scale of the machine boggles the mind. :argh:
Last edited by lambert on 18 May 2012, 17:53, edited 3 times in total.
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Post #33 made 12 years ago
lambert wrote:
Yeasty wrote: EDIT: I need one of these babies Here
Weight net 12,000 to 35,000 kg

The scale of the machine boggles the mind. :argh:
I'm gonna need a bigger shed !!
Last edited by Yeasty on 18 May 2012, 18:12, edited 3 times in total.
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Post #34 made 12 years ago
Yeasty wrote:I finally innoculated some slants last Friday :party: the prepared slants have sat under my desk for over 6 weeks which was a good thing as I have had a few failures. Not the medium but around the cap. I think this is because I had a bit of condensation in the tubes and this had run under the threads of the caps. Being slightly sweet from the medium it allowed mold to grow.
None were contaminated inside the tube but I had to ditch them as it would have been impossible to clean off, innoculate and be sure they were still sterile.

The 3 I innoculated have colonised wwell and will now go in the fridge.. :thumbs: I'm going to wash some yeast off my APA and make some more and possibly look into freezing.

Note: Pics to follow.
Yeasty, I never used that frozen sample I made the starter with. didnt trust it. Its still in my fridge and has never cleared properly either looks like its still in a cloudy suspension. I've ordered a load of sterile tubes and I'm going to start slanting. Looks easy enough and from waht I'm reading I can take a single colony from a slant and grow up to pitching level each time I want it. I see you had a problem with condensation, how do you actually avoid condensation in the slant? Doesnt it cool down with the lid on so this must cause some condensation?
Also, what sort of agar should I be buying? I see this stuff on ebay. Is there anything in particular to look for or is all agar the same?

Thanks

L
Last edited by Lars on 23 May 2012, 08:26, edited 3 times in total.

Post #35 made 12 years ago
Hi Lars

I've attached a PDF which is a cut and paste of Wolfy's write up off Jims forum. It explains the Slanting process and can be printed off.

Condensation is a problem, I think it was a problem for me as although I loosened the caps whilst cooling some of them seemed to tighten up !

The agar you can get from an asian supermarket, its sold as either Agar Agar or Chinese Grass powder and is cheap.

:thumbs:

Yeasty
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Yeasty's Yeast Slants (slopes)

Post #36 made 12 years ago
Yeasty wrote:Has anyone successfully dried yeast ? or heard of any one who has done it ? I think I have read about it somewhere :scratch: not sure if it was dried or just still damp/wet.

My idea it to try drying it under a vacuum. I can set up a vacuum pump to remove air from a space containing a yeast sample, at low pressures the water will evaporate at room temperature effectively drying the yeast. :think: Perhaps a test tube containing the yeasty inside a vacuum chamber ? perhaps with a one way valve so as to not let any air back in once the vacuum is released ??
I think I'll research it further and have a good think about it, feel free to pick holes in my idea :shoot: :shoot: the main point is will the yeast survive drying under a vacuum, I'm sure that how the big boys do it.

EDIT: I need one of these babies Here
directly from Chris white an Jamil Z's book under 'Long Term Storage' they say 'Desiccation is not a good option, as the process itself may introduce mutations'. Maybe why so many strains are only available in liquid form. Check out this table referencing storage methods:
Image
Last edited by Lars on 24 May 2012, 02:05, edited 3 times in total.

Post #37 made 9 years ago
Hello,
I plan to slant some yeast soon, i have all the equipment needed besides the pressure cooker. This evening i found in a store a 9 litre (2 gallons?) one, with this inscription: working pressure: 0.50 bar, max pressure: 1.1 bar. Those numbers translate to working:7 psi, max: 15 psi, so, for a good sterilization i need to use it at full capacity, or near that. I will probably buy it anyway as is on offer and i could use it for cooking, but do you think that it could be used for yeast slanting also?

Post #38 made 9 years ago
Bionut, if the Cooker can get to 240F, which would be 1.1 bar above Atmospheric Pressure, it will sterilize fine, if held at that temperature for about 3 hours.
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Post #39 made 9 years ago
Wow! 3 hours? I've read that some sterilize their equipment in 15-20 minutes... probably they have better cookers, or autoclaves.
How big should the flame be during those 3 hours? I presume that a small to medium flame would be fine, just to mantain the presure?

Post #40 made 9 years ago
Bio, the High heat involved will cause the Blow-off/Pressure-release valve to open, and Let Really Hot steam Escape, so keep the Heat at a level to hold the temperature/Pressure.
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Post #41 made 9 years ago
OK, i hope my future cooker will be able to rich that pressure, if not, will i be able to sterileze at a lower pressure? I what conditions?
I've read about the Tyndallization process, but i don't think that i could use it with agar medium.
Tyndallization essentially consists of heating the substance to boiling point and holding it there for 15 minutes, three days in succession. After each heating the resting period will allow spores that have survived to germinate into bacterial cells; these cells will be killed by the next day's heating. During the waiting periods the substance being sterilized is kept in a moist environment at a warm room temperature, conducive to germination of the spores. When the environment is favourable for bacteria it is conducive to the germination of cells from spores, and resistant spores do not form from cells
Source: Wikipedia
Last edited by bionut on 22 Jan 2015, 06:02, edited 3 times in total.

Post #42 made 9 years ago
Our aim is to kill wild yeast and mold spores so 15-20 minutes at 15psi (121c pressure cooker temperature) is proven to be sufficient for or brewing needs.

:thumbs:

Yeasty
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Post #43 made 9 years ago
I konw that, but i want to buy a cheap pressure cooker, without a pressure gauge, and i am not sure if it can get to 15psi. That's all i can afford for now. I will buy some sterilizing strips also, to check if it can get to that pressure.

Post #44 made 9 years ago
I use a cheapy pressure cooker with just 1 weight which gives me 15psi. I don't think a pressure gauge is a must have. I've made about 50 slants with it and only used about 20 of those for yeast the rest are in a drawer. Only 1 has failed and that is only 1 little colony of something.

:peace:

Yeasty
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Post #45 made 9 years ago
That's reassuring. I don't know what weight are you talking. Is that weight on the steam nozlze? If it is, why would a better pressure cooker would have 2 or more? Did you tested your PC or you just presume it gives about 15 psi from your results?
BTW, a friend of mine uses some medical grade antibacterial spray for sterilizing step, and when he uses the yeast just wash it with water purifing tablets. He is experimenting; but until now he got good results.

Post #46 made 9 years ago
Some pressure cookers come with different steam nozzle weights for different cooking temps,mine (second hand)came with just the one (15g) which according to the manufacturer results in an internal temp of 121c at 15psi.

:salute:

Yeasty
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Post #49 made 9 years ago
I want them to be the prettiest slants!
I used homemalted grains for making the wort, and in only 2 liters of water it turned very cloudy, with a lot of break, proteins, etc. Is not the usual cloudy wort that you get normaly with biab (i think the small volume of water is the issue, beside malt, of course). Also, the rootlets were still on the malted grains. I made a beer too with that malt, before bottling tasted good enough, i am waiting for carbing to get take a final conclusion :-)
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