I have a microscope and occasionally bother counting cells.klangers said:I haven't heard of anyone using a microscope to count yeast. Maybe there are people that do it (outside of labs) but I haven't heard.
The problem is that in order to see anything at that level you're going to have to invest in optical-quality petri dishes and smear the yeast on them real thin as you need a backlight in order to see the cells. I'm not sure how useful this would be at getting an accurate cell count (well, more accurate than other "macro" methods).
I do a bit of photography and one thing I've learnt is that cheap "optical" glass is rubbish. A decent microscope (ie capable of 400x without hideous aberrations or distortions) is going to cost a decent sum of money; there's no way around it.
Apologies if you already know this, but it just sounds like overkill to me and I want to make sure you're aware of the (potential) can of worms you may inadvertently open for yourself.
Have you tried training a few high output LED's at that mirror?verysupple said:Unfortunately I can't help th OP about what type or where to get a microscope that's suitable as I got mine for free (the uni was going to throw away a bunch of the old style ones with a mirror instead of a lamp). It's a bit over kill for yeast counting. I have objectives and eye pieces allowing up to 1250x but I struggle to get enough light using the mirror at those magnifications.
goshAzzA68 said:I bought a SEM a few years back, it set us back US$205k... but the exchange rate was favourably about 1.08˜1.10 at the time... very good for measuring the cell dimensions and finding cells with nodules/buds (where they separate to multipy). Of course the cells are very much dead, having been protien fixed (so they don't deform under very high vacuum), soaked in ethanol, put through a Critical Point Dryier, and sputter coated with about 25nm of gold/paladium, so they're not much use for brewing with anymore. We can get a full screen image of a single yeast cell though.
How did you test the viability? I've used methylene blue but that's not very accurate below about 90 %.dent said:What I find more useful is the ability to check the yeast viability - for instance, I had a batch of some english ale sitting in the fermenter, cold, for two weeks after it had fermented out. After kegging it, I checked the yeast in the trub - it was down to 30% viability!
That might help a bit, but you really need parallel light for the mirror to work effectively. I get plenty of light for work with yeast anyway. It's only if I go way up on the mag (above ~1000x) that I need more light.boddingtons best said:Have you tried training a few high output LED's at that mirror?
They only cost a few bucks, I use them now instead of photo lights in my lightbox.
(I still do a bit of product photography to keep the sherrif's from the door)
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