Author Topic: Microscope  (Read 1729 times)

Offline beerbrewinwizard

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Microscope
« on: September 02, 2012, 06:30:03 PM »
I am going to advance to a higher level in my yeast processing and I need to know what model, size, shape and magnification of microscope to buy. I also need recommendation on a hemacytometer. Is a Neubauwer a good brand? Thanks

Online Kaiser

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Re: Microscope
« Reply #1 on: September 02, 2012, 07:31:24 PM »
Welcome to the forum.

Here are some of my thoughts on microscope:

You need 400x magnification for counting cells. That generally means 40x objective and 10x eyepiece. It's also useful to have 1000x but only if you want to take a close-up look. My microscope requires special oil between the objective lens and the cover slide. I rarely use this magnification. These days I actually count at 100x by taking a cell phone picture of the complete fine counting grid of the hemacytomter and use ImageJ to count the cells.

I have the Neubauer style hemacytometer. This seems to be the most popular.

I got my microscope and supplies from Cynmar. The microscope (4x-10x-40x-100x, multiply this by the 10x of the eyepiece) was on sale for ~$160 and has only one eyepiece. Stereo would have been nice, but that was $100 more.

Other stuff you want to get is:

- Methylene blue. This comes in power form and you make a 1% w/w solution that is best stored in an eye dropper. you can use this for testing yeast vitality. Note that for poor yeast vitality, meth blue overestimates the vitality. But I wouldn't use yeast will less than 90% vitality anyway

- get a few serological graduated glass pipetes. They come in handy when diluting samples for counting. Also get a pipet pump. I use just one 10 ml pump for all my 1 ml, 2ml, 5ml and 10 ml pipets. 5ml and 10ml will be most useful for you.

- also get a few glass droppers. They are useful for taking samples

I think that's all you need to hit the ground running.

To quickly determine the cell count in an undiluted sample in a Neubauer hemacytometer you can count the number of cells in 4 of the smallest squares. That number will be the million/ml cell density. For more accuracy you will have to count the cells in a few of the 4x4 squares and use a formula I would have to look up this formula since I have it in spreadsheets. But you can also find it on the internet.

Here is a PDF of the Neubauer grid with indications about the size of the features: http://braukaiser.com/download/Neubauer_hemocytometer.pdf

Kai
« Last Edit: September 02, 2012, 07:41:14 PM by Kaiser »

Offline anthony

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Re: Microscope
« Reply #2 on: September 02, 2012, 08:52:26 PM »
Can you explain how you use ImageJ?

Offline thcipriani

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Re: Microscope
« Reply #3 on: September 03, 2012, 04:54:54 AM »
Be sure to check eBay.  I spen $40+shipping on a cheap student microscope that I've used for the past 3 years. http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=380248813512
Tyler Cipriani
Longmont, CO

Online Kaiser

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Re: Microscope
« Reply #4 on: September 03, 2012, 08:13:53 AM »
One more thing as I see the microscope on Ebay. I like having a mechanical stage. This shows moving the slide or hemocytometer with knobs and is easier to control than sliding it by hand.

Kai

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Re: Re: Microscope
« Reply #5 on: September 03, 2012, 08:29:44 AM »
Can you explain how you use ImageJ?

I use it in a less sophisticated way than washy it can do. I use the cell counter under Plugins->Anlyze-> Cell Counter. It counts  clicks made on the image and leaves a small marker so you know what you already counted.

I have to remember to post pictures  later.

before that I used a tally counter.

Counting cells add a lot of time to the brewday. I found it to be faster to use the microscope to establish the slurry density of commonly used yeasts and then pitch by weight.

on my last beer I estimated the slurry density to be 2 Billion/g and it turned out to be 2.6 B/g

Kai

Offline beerbrewinwizard

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Re: Microscope
« Reply #6 on: September 03, 2012, 06:08:39 PM »
Thanks for all the info. and recommendations.

BBW

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Re: Microscope
« Reply #7 on: September 03, 2012, 08:29:44 PM »
Here is a pic of cell counting with ImageJ. The picture shows one 0.02x0.02 mm grid. I tend to count 5 of them on one side of the memocytometer and another 5 on the other side.



This larger image shows the picture I take for counting with my phone camera. The opics are not the best and only the center 9 0.2x0.2 squares are reasonably sharp. That's good enough for me.

Kai
« Last Edit: September 03, 2012, 08:44:14 PM by Kaiser »