brew labs slants

[Mark1964]

Got a brew labs slant started last night has anyone used these. Showing no signs of life yet. How long do these take to get going. It came on an agar slope according to instructions you pour some sterile spray malt solution in the vial then shake to release the cells them pour into 300 ml of spray malt solution

 

[markp]

I've got a Yorkshire 1 in a starter at the moment.
It took 2-3 days to get going properly - remember, there isn't a lot of yeast on that slope to start with.
After 5 days it had fermented out, I then refrigerated it to get it to drop out and then added another 300ml of wort......going like a rocket now :)

Give it time Mark :thumb:

 

[adomant]

about 3 days, give a gentle swill from time to time to keep the yeast in suspension (if you're not using a stir plate that is)

 

[Mark1964]

Thanks for that was planning on using it at the weekend maybe a bit too soon really will see how it goes

 

[evanvine]

It took 2-3 days to get going properly

That's pleasing to know. My frozen yeast phials only take 36 hours!

 

[Mark1964]

According to brew labs you cant freeze this yeast

 

[evanvine]

According to brew labs you cant freeze this yeast

Oops, another thing I'm doing wrong that works

 

[Mark1964]

Is the yeast not freeze from them on their instructions they reckon it will kill the yeast

 

[evanvine]

I don't freeze until I've collected and processed the yeast from the ferment.

 

[shocker]

I wonder why the no freeze thing ? Is it because its a very low concentration and we usually rely on there being such a large amount of cells that some will survive ?

I dont know a whole lot of detail on yeasts as this consumer availability is a relatively recent thing as is the access to in depth details . However , I havent heard of a beer yeast variety that couldnt be frozen AT ALL , ever , before now . Still , as I said , I dont know much ! But I am keen to learn ....

 

[StubbsPKS]

From what I've heard (could be wrong :shock:), when you freeze yeast you risk rupturing the cell walls due to expansion. This could be completely wrong, but seems plausible bc if you freeze a beer bottle, the expansion causes the bottle to burst.

 

[shocker]

I thought that was down to the ice ! Maybe a combination of both , then :hmm:

 

[shocker]

Also ,as I said , maybe because we freeze such comparatively large amounts of yeast then maybe only the outer layers get killed off and the centre preserved , but with a slide culture you dont have the mass to protect the core . A theory , anyway.... :wha:

 

[Aleman]

I wonder why the no freeze thing ? Is it because its a very low concentration and we usually rely on there being such a large amount of cells that some will survive ?

As has been said, generally the problem is that ice crystals form in the cell and the expansion 'explodes' the cell. The usual technique when freezing yeast is to use some form of cryoprotectant, for example, glycerol which prevents the ice crystals forming. (Usually 25% water : 25% glycerol / 50% yeast slurry). I've tried this in the past using 'washed yeast slurry' and a domestic freezer which was not successful, although I do know others that have great success with the technique, but they are using much smaller volumes (2ml) compare to mine (50ml), plus they freeze the 'small' volume much quicker using dry ice.

How, and why, Jim's technique works I have no idea, as all the convention says it shouldn't

In a commercial environment (Brewlab for example) they actually do freeze yeast on slants and down to somewhere around -80C . . . but extreme measures are taken to ensure that the yeast is adequately protected against the cold, and they use a sterile mineral oil over the slant to provide cryoprotection for the yeast.

Why do Brewlab state don't freeze the slant? . . . You'll kill the yeast! There is of course nothing to stop you growing you yeast up to a healthy volume, and then freezing it taking into account the need for a cryoprotectant . . .but do NOT freeze the slant! Keep it at around 4-5C