Solubles Yield as a function of Grind and Dwell Time - Page 3

Coffee preparation techniques besides espresso like pourover.
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cannonfodder
Team HB

#21: Post by cannonfodder »

Here is a question; does conductivity change as heat changes in a solution? I am inclined to say yes based a couple of observations. So if you were going to use a TDS meter to check solids in shots between grinders not only would the dose/time need to be very close but the tested samples will need to have cooled to a predefined temperature. I would also agree with Jim in that the 3 way will suck some moisture back out of the puck so simply tossing a used basket on a scale has limited accuracy. JimS and Andy did a lot of work on this and baked a lot of espresso puck brownies in the process.

Dosing and Solids Extraction Retraction
Aspects of Espresso Extraction

As to the Clover, my two cents (disclaimer, I have only had a couple cups from one so take my opinion with that in mind) it makes a good cup of coffee. I have had better and I have had worse, would I pay $10K for one, nope. I would be more inclined to get a case of French presses and vac pots to be used at the table but it is a very cool gadget to watch. But then so is a vac pot.
Dave Stephens

Matthew Brinski

#22: Post by Matthew Brinski »

cannonfodder wrote:Here is a question; does conductivity change as heat changes in a solution? I am inclined to say yes based a couple of observations. So if you were going to use a TDS meter to check solids in shots between grinders not only would the dose/time need to be very close but the tested samples will need to have cooled to a predefined temperature.
Yes, they will vary roughly 1% to 2% for every degree of Celsius change that occurs depending on the meter. Some meters possess a function to compensate for this, but you need a baseline to start with.

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cannonfodder
Team HB

#23: Post by cannonfodder »

I know electrical conductivity changes as temperature changes so I assumed the same would be true of a solution. My TDS meter has a temperature probe built into it, probably just for that reason.
Dave Stephens