[foodhackingbase] Let's enable yeast counting

[Mark Meyer]

Hi all,
I've found myself wanting to be able to work reliably with wild yeast cells for my beer. One way to enable this is to use a lot of patience and experience. The other would be to do a proper cell count and go with that. So far the hurdle has always been that a microscope sets you off by a lot of money.

See here for the procedure:
http://www.nexcelom.com/Applications/cc-05-counting-yeast-cells-using-a-hemacytometer.php

Now however there's Foldscope: https://www.foldscope.com/

It's an origami microscope that's able to image single yeast cells (from what I've seen).

There's also this note: https://www.microsoft.com/en-us/research/wp-content/uploads/2017/09/hotmobile17-blood.pdf

That note presents essentially the same technique with a cheap mobile phone microscope, but it's for complete blood counts.

So here's what's needed (partly per person):

  - methylene blue (aquarium supplies, like 7 eur for 25g) for staining the cells, this eases identification of dead and alive cells
  - counting chamber/hemacytometer (china, around 1 eur)
  - micropipettes (sadly not cheap) for accurately measuring volumes
  - foldscope (1 eur)
  - some kind of fixture, be it paper or 3d printed, that mates the foldscope to the hemacytometer
  - some general lab equipment for measuring

I've got everything on that list, with the exception of the foldscopes and the fixture. Those need to be ironed out as soon as Foldscope becomes available again. Currently they don't sell Foldscope classroom sets, because of production shortfalls, but I intend to buy some as soon as they become available again.

I already enlisted some locals as testing subjects and hope to be starting with this project in May. Hopefully I could present a workshop later in the year. The idea is to be able to set the cost at 10 eur and provide people with a Foldscope, some staining agent, counting chamber, plans for the fixture or fixture itself and maybe some general equipment to take home. Note the exclusion of the micropipettes.

Cheers, Mark

-- 
  Mark Meyer
  mark at ofosos.org