Brewers Yeast

[robkimberley]

Hi there

 

If I have a liquid that contains yeast and i boil it, does anyone know what temperature the yeast will die? Also can i use a microscope to measure the size of the yeast? As i may filter the liquid afterwards to remove the husks.

 

Thanks

 

Bob

[insane_alien]

well, they'll die at most temperature but its not like it gets to a certain temperature and then suddenly all the cells die.

 

i think 60*C is sufficient to kill some of them, although to kill a significant fraction in a reasonable time then you are probably looking at 110*C or so.

 

you could use a microscope to measure the size of the yeast, they are a few microns in diameter so should be easily visible.

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well, they'll die at most temperature but its not like it gets to a certain temperature and then suddenly all the cells die.

 

i think 60*C is sufficient to kill some of them, although to kill a significant fraction in a reasonable time then you are probably looking at 110*C or so.

 

you could use a microscope to measure the size of the yeast, they are a few microns in diameter so should be easily visible.

[Sisyphus]

I'd say 60 C is probably more than hot enough to kill all of them. You shouldn't need to boil it.

 

Can I ask what you're doing? It might actually be inadvisable to boil whatever you're working with, depending on what it is and what your plans are. (If your goal is just to examine dead yeast, then I guess it doesn't matter.) I should also note that it's actually totally harmless to consume live yeast, if that's what you're worried about. I've imbibed "live beer" many a time.

[jdurg]

I'd say 60 C is probably more than hot enough to kill all of them. You shouldn't need to boil it.

 

Can I ask what you're doing? It might actually be inadvisable to boil whatever you're working with, depending on what it is and what your plans are. (If your goal is just to examine dead yeast, then I guess it doesn't matter.) I should also note that it's actually totally harmless to consume live yeast, if that's what you're worried about. I've imbibed "live beer" many a time.

 

"Totally Harmless" depending on who you're around. I've consumed many a "live beer" and let's just say that those around me the next day didn't find it too "harmless".

[insane_alien]

I'd say 60 C is probably more than hot enough to kill all of them. You shouldn't need to boil it.

 

not really, i am working on designing a bioethanol plant design and before the yeast get seperated out they undergo heat treatment at 50*C to temporarily stop them producing CO2 but still retain cell viability. 60*C will not kill all of them unless it is for several days.

[Sisyphus]

not really, i am working on designing a bioethanol plant design and before the yeast get seperated out they undergo heat treatment at 50*C to temporarily stop them producing CO2 but still retain cell viability. 60*C will not kill all of them unless it is for several days.

 

Alright, fair enough. I was just going brewing methods. Of course, the goal there is always not to kill the yeast, so I guess I don't really know what I'm talking about...

[Mr Skeptic]

not really, i am working on designing a bioethanol plant design and before the yeast get seperated out they undergo heat treatment at 50*C to temporarily stop them producing CO2 but still retain cell viability. 60*C will not kill all of them unless it is for several days.

 

But are you working with brewer's yeast? I thought that for bioethanol they liked heat-resistant strains for higher efficiency.

[insane_alien]

yep, just regular brewers yeast. it has a better yield of glucose to ethanol than the heat resistant strains but even the heat resistant strains are pretty sensitive to heat.

 

there are some bacteria that are best around 50*C but they're crap compared to yeast.