Slanting yeast

[mordantly]

the pressure cooker creates an environment of 230-250F depending on pressure of the steam. in 30 minutes at 250F(15 psi) all known life ceases to exist. boiling would create a sanitary condition, but it still will contain some ammount of yeast spores, etc that will pose a problem if given long enough.

 

[krops13]

A quick comment on incubation. The lids of the media should be left cracked open for proper air flow. The yeast need a gas exchange when growing. I have down 10+ cultures this way and only one has gotten infected with ants.( no mold or bacteria). If your having troubles with mold it could be from you hand touching the lid when you " burp" your media.
source: microbiologist ( I'm not one know a few at work)

 

[jppostKW]

I have been slanting for a while using gelatin i made up an original 25 slants and just inoculated my last 5 with Pacman i harvested from a couple mocha porters I have a healthy yeast colony in each but the gelatin is starting to deteriorate ( have liquid on the bottom )with the yeast chilling in that they have been in there for 3 days can i reslant onto newly made slants with agar or should i put my self thru the pain of having to drink a shakspeare stout or 2 because it is so rough!!!

 

[krops13]

I have had this happen to me a few times. The problem fixed it self when I left the slants cracked open while inccubation. I know scary right? I was real nervous to do this at first but with the yeast growing on there it creates a postive pressure. And once the yeast take over its a bit harder for bact. mold and what not to get a hold.

 

[mordantly]

provided the slant doesn't dry out during that time.

 

[bill2penn]

I came across a nice set pictures of yeast propagation on Flickr here

http://www.flickr.com/photos/caylan/sets/72157607478973676/detail/

Perhaps this is a member of the board?

Bill

 

[Saccharomyces]

How important is the pressure cooker to produce the blank slants? wouldn't boiling the dme/ager cause it to be sanitary and if not tech. sanitary at least wouldn't the level of heat to boil it also kill all the germs? couldnt you refrigerated the blanks after filling the slants with your dme/ager mix? What exactly does the pressure cooker perform?

You need to use the pressure cooker because common bacteria and mold spores won't be killed by a boil. It's a numbers game.. when you are building a starter from a tube or pack with 100B cells vs. a slant which will grow up to about 10M cells that is a huge difference in ratios. Even a few spores will have a chance to grow and will sour your beer.

 

[Saccharomyces]

provided the slant doesn't dry out during that time.

I usually let my slant vials sit for 2 weeks before tightening the caps and storing so they have plenty of time to dry out. I went on vacation and left some harvested Sierra Nevada yeast out for three weeks, that was obviously too long to incubate because three of four had grown to the point gas pushed the entire slant out of the vial.

 

[Caylan]

I'm the owner of the flickr stream cited above.

Here's another link that highlights the yeasty beasties: http://www.flickr.com/search/?w=27291052@N00&q=yeast+culture&m=text

If anyone has any specific questions, let me know.

 

[mordantly]

so you DO dry your slants out?

 

[Caylan]

Don't worry about drying your slants. You're just risking infection. My slants have some liquid condensate but it doesn't interfere with yeast growth. After inoculation of a slant you should replace the cap but do not tighten to seal. Let incubate for 3-5 days at ~80F until satisfactory yeast growth occurs, then seal tight, put in a plastic bag, and refrigerate. The reason for the incubation period is to build a colony and expose contaminants.

 

[ChillyP]

So I noticed that my slant I just made have about a tiny drop water in them. I think they'll be okay.

 

[krops13]

Wanted to show you guys the slants I made with the help of this thread. Im leaning one out on the shelf to see if anything grows. I hope not. Thanx again this place rocks:rockin:

 

[jason.mundy]

Krops13

Good pics... And nice use of the coat hanger to make your slant. It looks like that angle gave you a lot of surface area inside the tube.

It doesn't look like your slants are in glass. Is this true?

Did you run them through the pressure cooker?

If they are autoclavable, what was your source.

Thanks, Jason.

 

[krops13]

They are glass. I prossesed them at 13-14lbs for 15 minutes. I pit a plastic plate in there with the slants but it melted.

 

[Doog_Si_Reeb]

If you let the vials cool a little too long, such that the Agar/DME solution starts to solidify before it is stored at an angle, can you reheat the vials in the pressure cooker for another 15 minutes to return it to a liquid form? Or should you empty the vials and start over?

Thanks!

 

[mordantly]

place in water, bring to near boil or so, and re-set at desired angle. but don't remove the caps! i just re-slanted the angle on my 24 in-stock so i got as much surface area as allowed without touching the lid area.

 

[Doog_Si_Reeb]

Thanks! I reheated them this morning and they returned to a nice liquid form. The vials are now sitting at an angle forming nice slants.

 

[Snausages01]

Thanks for the write-up.

 

[mordantly]

i finally got a cheap alcohol lamp on ebay.. one that can sit at 30*, 60*, and 90*. what a difference it makes vs a candle..... no more carbon deposit on my nichrome loops.

 

[displacedtexan]

I don't have a small scale and am having trouble measuring the 2.5 grams of agar.

I used 1/2 teaspoon and my agar hasn't set after about 12 hours.

Anybody know the volumetric equivalent of 2.5 grams of agar (e.g. 2.5 ml, 5 ml, etc).

Thanks!

 

[mordantly]

powder or jelly? if it's powder, ummm i can check. the jelly, can't you estimate like a cube of butter?

 

[displacedtexan]

I have the universal beer agar powder from Midwest Brewing Supplies.

Thanks for the help!

 

[dfohio]

My Agar is in flakes. 2.5 grams = 1Tbsp for these. Not quite sure about a powder though

 

[displacedtexan]

My Agar is in flakes. 2.5 grams = 1Tbsp for these. Not quite sure about a powder though

Got it, thanks! I'll give it another try in a few days!

 

[JimE]

im sad to report, on day 5 or 6, no visible life of any kind on my three test-slants of the previously mentioned jell-o media. how long should i wait at 65-70F before i scrap the test? i think the stuff is too dry for growth.

I wouldn't use regular Jello. Try Knox or some other brand of unflavored, unsweetened gelatin. Let your wort provide all the nutrients. How did they turn out after you waited another day?

 

[mordantly]

I wouldn't use regular Jello. Try Knox or some other brand of unflavored, unsweetened gelatin. Let your wort provide all the nutrients. How did they turn out after you waited another day?

it was a complete failure:

melted at room temp
very little growth (was impregnated in media)
co2 created pockets in media
media moved around in vials
a complete pain to clean the vials
was a tricky ratio of jello/dme

pictures here

https://www.homebrewtalk.com/f163/slanting-yeast-133103/index3.html#post1730057

 

[chuckjaxfl]

I don't have a small scale and am having trouble measuring the 2.5 grams of agar.

I used 1/2 teaspoon and my agar hasn't set after about 12 hours.

Anybody know the volumetric equivalent of 2.5 grams of agar (e.g. 2.5 ml, 5 ml, etc).

Thanks!

Have you considered a low-end reloading scale? Ammunition reloaders work in 0.1 grain (or 0.000228571429 ounce, or 0.006479891 gram) measurements.

Here is a low price, low tech, high precision scale. Accurate to 1/20 grain, allegedly. It will only measure up to about 1/4 ounce, though.

For a few dollars more this one is digital, and will measure up to about 3.5 ounces.

 

[riromero]

I got one of these little scales from Harbor Freight to measure brewing water salts...

http://www.harborfreight.com/digital-pocket-scale-93543.html

I didn't have much hope that it was accurate, but I calibrated it with volumes of water and it was right on the money.

 

[pbarning]

Would I be correct in assuming that the pressure cooker provides a means of sterilizing both the media and vials?

I am thinking about boiling the media and funneling it into the vials. Then I'll put the filled and partially capped vials into a beaker that will be placed into a boiling water bath. I will cover the bath (pot) so as to allow the steam to make contact with the vials. This should be sufficient for sterilizing the vials, right?

-or-

Could I simply boil the media and funnel it into the vials and then place the partially capped vials into a stove for a period of time? Like a ghetto autoclave?

Bottom line is that I do not own a pressure cooker, but there should be alternative means of successfully sterilizing the media and equipment.