Inconsistent grind volume when dosing by weight

Beginner and pro baristas share tips and tricks.

Postby Swong46 » Jun 26, 2018, 2:11 pm

Hi all,

I have not had this problem until recently. I have a Breville Smart Grinder Pro and the built in grinder in the Barista Express. Both beans I had in there, when dosed to 18g, would not fit in the portafilter after tamping.

I've used a dozen different beans and they all tamped to a certain point on my tamper. These two beans now have the tamper sitting about 20-25% higher in the basket. And then I am getting insane flow and gushing out of the portafilter spout.

The problem with the grinds not fitting, is that a grind setting issue or?

Prescott CR

Postby Prescott CR » Jun 26, 2018, 2:19 pm

Are the grinds noticeably larger? It's possible the top burr is loose, it wouldn't hurt to take it apart and clean it.

That said- dark coffees will fill a basket more than a lighter roast at the same weight. That is, more volume and that would explain what's happening. I'd say tighten the grind but you already tried that, right?
★ Helpful


Postby emradguy » Jun 27, 2018, 8:30 am

What he said...and also, do you weigh the beans or the grinds? In other words, are you weighing the dose before or after you grind it?


Postby Swong46 » Jun 27, 2018, 1:13 pm

I am only weighing it after being ground. But I did verify the scale was accurate to two other scales. One of them is pretty high end and fine resolution.
All the beans are done for so I'm moving on oh well. But with a finer grind, it compacts better but tasted over extracted. So there was a fine converging point of extraction time and compaction. As I adjusted it one notch coarser, it wouldn't compact and then seemed to be channeling. It also made some crazy thick and chunky crema. Still learning here!

Beans were a Indian Monsoon Malabar from Santa Cruz Roasting Co. but they couldn't tell me when the roast date was...

Put in my usual "Drive Coffee" branded beans and dialed it coarser 3 clicks and I'm back to happy days!


Postby viveur » Jun 30, 2018, 8:36 am

Grind volume can vary by bean, temperature, and humidity. With some beans a rather large grind adjustment is needed, and I also need to adjust during the day if the temperature or humidity change (I have large swings of both in the summer since I keep the windows open overnight, and close them during the day - the lower temperature and humidity in the morning means I need a coarser grind then).