Effect of hole size in basket?

[S.L.]

I have two Olympia's, one at home and one at work. The work machine just got up and running, and I've been tearing my hair out trying to get the same results as at home. I just looked today on a lark and noticed that the holes in the basket (double) on the work machine are almost twice as big as my home machine. I haven't swapped them yet to nail it down, but it seems to make sense that this would affect what goes in the cup.

Is there a standard for hole size? I have to scrounge up some more baskets and test...

[timo888]

Baskets varied in significant ways over time. See

See http://www.home-barista.com/forum...t-t1452.html#20682

Regards
Timo

P.S. Brew pressure is a result of a number of factors, including the flow-rate of the fluid exiting the system. The number and size of the holes in the filter affect the flow-rate through the filter.

[S.L.]

Interesting reading- I think I will steer away from Olympia and try some Elektra Microcasa baskets. The Olympia basket with the smaller holes seems "right"; when I grind for a correct pressure and timed pull with the the other one I end up with chewable solids in the crema. Anyone know a source for Elektra parts in Europe?

[timo888]

The replacement baskets work well when used in an older (1975 Club) Olympia portafilter, whose dimensions are slightly different from those of the 1992 Cremina 67; the basket sits lower in the older of the two portafilters.

Regards
Timo

[S.L.]

I measured the holes with a microscope in a jig borer at the shop. They aren't exactly round so plug gages were out! I have a single and two double baskets between my two Creminas. The single and the "good" double had holes that averaged around .30-.35mm. The funky basket had hole sizes between .60-.70mm, must have been a Friday afternoon when that one went out. There's no way I can pull a shot with it without noticable grinds swimming on the crema. The upside is that I finally played around with the single basket in all the shot pulling and I think I may be a convert!