Morning coffee: An observation of particle size, consistency, and drainage

[Cruiser]

If you have a pour over carafe and grind your own beans, try using different grind sizes and watch how well water drains through them. It’s a fun little demonstration.

Obviously, finer grinds slow the drainage of water through the beans, but something else becomes apparent. Different bean particle sizes separate themselves with each pass of water. Smaller particles migrate to the bottom of the filter and the larger sizes to the top. With each pour, drainage slows because the smaller particles settle in the bottom of the filter.

There are probably many factors that contribute to this process, and this is a casual experiment at best, but I think there’s something going on here that we can learn from. At the very least, it shows that substrate size discrepancies do affect particle distribution and drainage over time.


Different particle sizes pre pour over.


After the second pour of water


By the fifth pour. Larger and unground beans have settled in the top of the filter.

Drainage is much slower by this point.

 

[PonderingSage:]

This is a good analogy. Glad you’re thinking about Bonsai first thing in the morning… before a cup of coffee even

 

[August44]

Hold on here a minute...I would guess that coffee beans float initially until waterlogged. The smaller the particles, the faster they will become waterlogged and the heavier they become...and down they go while the bigger particles are floating, or something close, and will be closer to the top. Make sense? I'm done! Thank you....

 

[woodkraftbonsai]

Hold on here a minute...I would guess that coffee beans float initially until waterlogged. The smaller the particles, the faster they will become waterlogged and the heavier they become...and down they go while the bigger particles are floating, or something close, and will be closer to the top. Make sense? I'm done! Thank you....

This was my first thought upon seeing this as well, as my bonsai soil particles do not float (unless Perlite is involved... hmmm).

Also, I do believe you should probably use a finer grind for your pour over there @Cruiser otherwise that looks like a waste of beans

 

[rockm]

I don't know if this is a good analogy for bonsai soil, particularly inorganic soils. Coffee beans are basically wood--they are technically a "stone fruit."

That means they tend to float, unlike clay, stone, etc. which are denser. Pumice may be an exception...

 

[Cruiser]

Hold on here a minute...I would guess that coffee beans float initially until waterlogged. The smaller the particles, the faster they will become waterlogged and the heavier they become...and down they go while the bigger particles are floating, or something close, and will be closer to the top. Make sense? I'm done! Thank you....

Good points. I wasnt controlling for other variables.
I just so happen to be making more coffee at this moment.. It appears that the unground and larger beans do float. I’ll try re-saturating to see how it affects things.

 

[Cruiser]

My initial intention was to share a quirky observation, but Old Lady Science demands further inquiry.

I repeated the “experiment” with saturated coffee grounds.

Used grounds were left sitting in water for an hour or so until there were no more floaters… (The couple in the photo were removed)

A reminder to start scheduling regular colon screenings at 45.



Pre pour-over. Different saturated particle sizes mixed throughout.


After 10 or so pour-overs. There appears to be no change in distribution of particle sizes.


So it appears that y’all were correct. The particle distribution/separation had more to do with saturation and buoyancy than with varying sizes...

Next I’ll try using straight unsifted pumice..