Declumping to measure fine grind distribution.

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Sugarbeet
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#1: Post by Sugarbeet »

I've been recently interested in finding out why is it that certain fairly fine grinds taste different to me and I wanted to simply take few microscope photos, run them through some processing software and get good grind distribution...

But it's not so easy mainly due to clumping of tiny fines and them sticking to larger grinds. (a lot of 10 micron and smaller fines can hide on a surface of one 300 micron grain).

For best results I'd have to separate these grains and take photos with them back lit. This picture is here to show the problem... They don't want to separate. I guess one solution would be to use a solvent to suspend them in, then let them slowly drop off onto a microscope slide, but what liquid to use that will at the same time wet even the smallest grains and not dissolve the solids, nor swells them etc?

Is this a solved problem? If so what's the solution? Has anyone else managed to find a better amateur method to get a grind distribution of tiny fines?

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yakster
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#2: Post by yakster »

-Chris

LMWDP # 272

jpender
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#3: Post by jpender »

I have to believe it's a solved problem. Sample preparation for particle analysis would depend on it. It's likely different for different substances. Coffee probably de-clumps in water but since it is partially soluble that would seem to me to likely affect the results so maybe some other solvent would be a better choice. I've been curious about this.

Take a look at this old thread: Titan Grinder Project: Particle size distributions of ground coffee

The author talks about both wet and dry analysis and how the results aren't the same. Maybe there is no ideal method, just compromises and approximations.

What Yakster is suggesting is intriguing. Would spritzing the beans with 20mg of water per gram of beans prior to grinding greatly reduce the clumps? That would be an easy experiment to try.

Sugarbeet (original poster)
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#4: Post by Sugarbeet (original poster) »

Thank you for the link to the old thread. It's very enlightening.

I haven't had a chance to do the really wet beans experiment yet, but it's on my list of things to do for sure.

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RapidCoffee
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#5: Post by RapidCoffee »

jpender wrote:Take a look at this old thread: Titan Grinder Project: Particle size distributions of ground coffee

The author talks about both wet and dry analysis and how the results aren't the same. Maybe there is no ideal method, just compromises and approximations.
Looking back (over 16 years!) I'll add that the fines peak appears smaller, and the large particles peak bigger, in the dry analysis. I'd guess this is primarily due to clumping.
John