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#1 | ||
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Senior Member
Join Date: Aug 2009
Location: Twin Cities, MN
Posts: 1,319
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#2 |
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Huge Member
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I prefer freezing, but only because i can store them for longer periods. I have at least 50 tubes of various yeast in my freezer. I have never grown on slants.
BTW, I get glycerine at Walmart. It is in with the hand sanitizers and is very inexpensive.
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Under the wide and starry sky, Dig the grave and let me lie. Glad did I live and gladly die, And I laid me down with a will. This be the verse you grave for me: Here he lies where he longed to be; Home is the sailor, home from the sea, And the brewer, home from the mill. |
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#3 |
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Senior Member
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ShortyJacobs:
I've successfully made slants for yeast using gelatin and wort, instead of having to hunt down agar-agar. A thick wort/gelatin solution, cooled at an angle in a small vial, makes a workable slant. Also, I've recultured slants that were over a year old. I'm not saying my technique is great, or that I'm not slowly mutating my strains -- I'm just saying that good results can be had from very modest equipment.
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#4 |
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Senior Member
Join Date: Jul 2009
Location: Jupiter, FL
Posts: 323
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Agar is just a type of gelatin. Of course for yeasts...you'd make an agar medium that uses Maltose. (DME & Agar) There are different agar mediums for growing different things.
The main advantage of a slant or petri dish with agar is...you use a sterile nichrome wire loop to transfer a streak onto the agar. Individual yeast cells multiply over time, as you incubate...and visible cell colonies appear. When you go to make a yeast starter...you sterilize your loop again...and pick up one colony and transfer it to a sterile wort starter. This makes it easy to get VERY PURE yeast cultures. With other methods...you could have a mix of who knows what in there. You can even buy a microscope and prepare slides to look at your yeast... It's a pain in the butt to do this though. I kept a yeast bank on mini petri dishes for a few years. I leave all that to the big boys now...and just buy a slap pack. I then chain brew..dumping the yeast from one secondary, into the next primary...untill all my kegs are done... Then I take a hiatus. I buy another slap pack the next time I start the pipeline up again. |
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#5 | |
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Huge Member
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Quote:
BTW, for most > 1.050 beers, one smack pack technically is not enough. At least it is not the proper pitch rate for a fast start to avoid all sorts of admittedly minor flaws. Therefore, you technically still should be making a starter and building up the yeast count. Of course, when you dump you wort onto a yeast cake you have more than enough yeast!
__________________
Under the wide and starry sky, Dig the grave and let me lie. Glad did I live and gladly die, And I laid me down with a will. This be the verse you grave for me: Here he lies where he longed to be; Home is the sailor, home from the sea, And the brewer, home from the mill. |
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#6 |
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Senior Member
Join Date: Oct 2007
Location: QCA, Iowa
Posts: 805
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#7 | |
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Senior Member
Join Date: Jul 2009
Location: Leominster, MA
Posts: 666
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Quote:
I think 3 months is a pretty conservative estimate for slant life. at least from what I've read and heard. I just started slanting recently, but my first step up from a slant was over 3 months after I slanted them and there was no issue with getting it going. |
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#8 | |
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Senior Member
Join Date: Oct 2008
Location: Vancouver Area - Canada
Posts: 631
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Quote:
Agar is a polysaccharide whereas gelatin is a protein - so there is one difference. Also Agar is very sturdy and wont melt until its temp gets near to boiling water and gelatin will start to melt at room temperature. Agar seems expensive when you buy it but you use just a little bit of it and the powder lasts for a long time - its easy to source by mail order. Also a lot of health food stores will stock agar powder. Picking a yeast colony from a plate or slant will ensure that you get exact duplicates of the primary cell that landed on that spot on the plate but it doesn't guarantee that the colony in question is not a mutant. Whew...now that the nitpicking is out of the way. I find slants very convenient; they will last well at least 9 months (haven't tried longer) in a conventional frost free refrigerator (maybe longer in a non frost free model). Its very easy to get a starter going from a slant - yes you still must do a starter- but it takes more time to get a culture up and running from frozen glycerine. I don't know the viability of frozen glycerine yeast in a conventional freezer (temperature cycles for it to remain "frost free" damages the cells) but they will easily last 2 years in a non frost free -20 Celsius old style freezer and can last 5+ years in a -80 research grade freezer.
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