Espresso with smaller baskets, learning from Lever machines
Looking back at the history of espresso machines, and especially with lever machines, you find that the 58mm basket used on 9 bar machines, is not so common. Smaller diameter baskets are really common. And lever machines are known for making ultra-smooth, easy-drinking espresso.
I long thought that 53mm baskets (such as those on Dalla Corte machines) was something I wanted to experiment with. I asked Ben to draw me a design for a 58mm->to->53mm basket, but in the word of COVID, no manufacturer wants to play with pure R&D with us.
Last week, from our tamper supplier, in arrived a variety of 58m baskets that they make, that have smaller output diameters. We measured them at 37mm, 41mm, and 52mm.
Going from 58mm to 52mm may sound like a small change, but this presents a 25% reduction is surface area of holes. Holding the dose weight constant, you get a correspondingly thicker puck as well. Going from 58mm to 53mm with a 15g dose, gives you the same thickness puck as if you'd gone to a 18.75g dose in the 58mm basket. That's a big change.
Theoretically, thicker pucks should channel less. I've definitely noticed that our 10g basket is almost impossible to make good espresso in without channeling, and I've been wanting to work on that. My assumption is that the puck is just too thin and tends to fall apart very easily.
I asked my in-house coffee expert Paul to work with my engineer Alex, and do some experiments. Alex previously designed a 3D-printable tamper specifically for our 7g basket, and I think special tampers will be needed for the baskets above too.
Initial tests gave us the results we kind of expected: the 52mm vs 58mm basket gave us a thicker shot, and much, much smoother, both at a 15g dose and the same grind. I've asked Paul to perfectly dial in the grind for each basket, and come back to me, as I think the 58mm basket will need a finer grind in order to be optimized, than the 52mm needs. I'll report back what we find.
Has anyone here also done comparisons of baskets that fit 58mm portafilter, but have a smaller bottom hole surface? What have you found?
We've absolutely found that how close the shower screen comes to the puck, greatly affects espresso thickness and the risk of channeling. I would expect that puck thickness would also have a strong effect. Thicker pucks should be easier to make, and smoother in flavor when using low doses.
However, if you move to 18g doses, I suspect that the 58mm basket is a more appropriate size. The puck would get too thick. Or will it?
Would love to hear from you on this, if you've tried these sorts of baskets, dialed in the grind, and compared.
-john
Update: this led to our waisted baskets, which you can find here: https://decentespresso.com/basket
Updated 2021/10/26