Going to get this up as a placeholder more than anything while I remember it.

When I was working for Mill City, I paid more attention to density. I want to get back to that. What triggered that was a comment John made about the current Yemen coffee Royal has as a Crown Jewel. Royal remarks on how important it is to watch heat application on the Yemen. To me, that is a dead giveaway that the coffee isn't dense.

For lack of better lab instruments, I grabbed a rubber 2C pitcher. Filled it to the top with:

Yemen: 414g
Ecuador Gonzanama: 442g (Royal Crown Jewel)

That tells me, easy on the heat, way back. Will be doing more reading on density and roasting and will bring back any good stuff to this thread. Remember Joe Marocco had a good Youtube I did with him at Mill City if I can find it. Chris has a good article over at Royal. Stick with it as he makes his point at the end of the article.

https://royalcoffee.com/green-coffee-an ... v-density/

Also going to start weighing "2C" baseline for every coffee I get and writing it down. Getting too casual.

2C? 2 cups?

What happened to metric?

ugh, I hate it when the delete button doesn't work.

dabrjn wrote:2C? 2 cups?

What happened to metric? :D

Metric? Man I finished high school in '66. I grabbed what I had, a nasty old 2 cup Rubbermaid pitcher off my basement workbench which I used years ago for an ashtray.

Metric, think 473.18 ml but then again, I am filling to the top of the container, not to the 2C line <grins>. Anyone following along in the hopes of finding a scientist is going to be sorely disappointed. This is strictly a base level comparison.

Measuring density is tricky without knowing moisture content.

Both Yemen coffees I've tried have had very low moisture content...in the 8% range. That alone would make me go easier on heat, but the seeds are usually very small which would double-down on that.

Dave,

Ahhhhh Mr.Wizard. I remember that show from when I was a kid in the late 50's. He taught me a lot. I actually met Don Herbert (Mr. Wizard) in the mid 80's when he was trying to get money from a friend of mine at NSF who funded his shows. He was still talking science.

david

Almico wrote:Measuring density is tricky without knowing moisture content.

...

So much of the density question is of itself a matter of moisture content. I believe they are inseparable in the discussion. Just interested in once again measuring a coffee's density before I begin roasting it compared to others I have roasted (clearly water is a component of that) and how that impacts the roasting approach I will take. Always curious about the practical, not the pure theoretical.

I tried measuring density, but I felt my numbers indicated my tools were inadequate.

I used a jar (about 400mL), filled it and weighed it. There is so much more that goes into filling a jar with beans than just density. The size, shape and how I fill then all made big differences.

A liquid displacement method seems much better. But to accurately measure all these things, we need $100's of dollars in equipment.

That's a good point about water content also. In my research, baking 100g of green beans at low heat overnight is the best way. You still want a scale that measure 0.01 grams in order to get an accurate decimal on your %water.

In the end, I found it was easier for me as a home roaster to just let it rip. If I find a bean wants less heat, I give it to them. I'm not roasting 75Kg batches were a mistake is so expensive.

I'd love it if there was an inexpensive, easy way to measure moisture content.

Rickpatbrown wrote:...
A liquid displacement method seems much better. But to accurately measure all these things, we need $100's of dollars in equipment.

....

Absolutely, but let's not the achievable suffer for the perfect. We are home roasters, seeking to add to the knowledge bin, or that's how I look at it.

So how do you actually go about using density in your roast plan? Do you decrease energy across the board to make the whole roast stretch? Or are there certain parts if the roast where high or low density really starts changing things.

It's pretty amazing to me that 350 grams of green coffee can behave so differently depending in its properties.
Some take an incredible amount if heat to push through the roast, others take off like an rocket as the slightest of flame.