Hi there,

I'm struggling to get a decent extraction from my double filter/basket (compared to excellent extraction from my single filter). The double is under extracted. I have 2 Expobar 600 ODG grinders - one for decaf and one for normal - that I use with an Expobar brewtus 4. The beans are freshly roasted and as I said, the single is really great. I tamp the double much harder than the single, but cannot get a good extraction. I've spent some time tuning the grind size and volume and the tamp pressure, but I need it to work consistently for both double and single baskets. I'm using the stock expobar porta filter and baskets.

Is the problem with the basket? Some advice will be much appreciated.

Thanks,
Peet

I wish I had your problem Peet

Maybe its your coffee?

Traditional Italian blends are supposed
to work at the same grind for both singles and doubles.

I have had a hard time making singles work with
the coffees roasted here in the U.S., they seem to be
geared for higher doses.

No sure it would help much, but you probably dont need
to tamp that hard.

Single baskets are a pain in the ass lol, but seems this is the opposite for you. Not sure about your double issue, never really had trouble dosing/dialing a double on mine or friends machines. Actually nobody I know uses the single basket, most have used that basket to modify and turn into some pressure/temp reader. If I wanted something smaller, I'd just pull a ristretto from the double.

What beans are you using? Tamp should be the the same, consistent whether single or double. Maybe a coffee that doesn't like being up dosed to the double range?

Thanks for the replies. Interesting that the beans may have some influence.

What I'm going to try is to dial it in for the double, extend the pre-infusion time for the double, and then try to match it with the single. I'm also going to try some different beans to see if that makes a difference.

Did I misunderstand that, or were you not dialing in before? Were you using the same grind settings for the single as you were the double and just dosing more?

I'm afraid this is likely user error. You'll have to find something that works for you trying things like a nutating tamp, different dosing techniques (fill the corners of the basket, dose while the grinder is running, WDT, Nutating Tamp, etc.). Dosing/distributing for a single basket is different from a double, as evidenced by most people having more trouble on singles. It appears the same works the other way around.

Peet,

Also make sure you are using consistent brew ratios, weighing
the amount of dry coffee and extracted liquid.

Thanks. Cmin - I dialed in for the single and then tried to echo the extraction with the double. It's clear from your replies that I have some learning to do.

Bostonbuzz, appa, I have now started from scratch. I dialed in the double - much finer grind setting. Dosing and tamping differently and things are getting really nice. I worked through quite a bit of material/theory (and beans), and I'm definitely learning to refine my skills and taste.

I appreciate the advice - just when you think you know what you're doing, it seems you're just starting out again...

yeh each will have different dialing needs, sounded like you dialed in for a single, then just doubled the dose and kept the grind settings same for a double lol .... live and learn . As far as tamping just be consistent. Can try other stuff like WDT which is what I do (I cut a little yogurt container to fit and stir with a needle), I hardly ever get a spritz or bad extraction since starting that a few years ago.

Thanks cmin - I'm learning Thanks for all the advice - I'm already at 100% improvement.