I use the Rancilio double basket most of the times and also have a triple which has a very similar pattern (with no connection between each hole). When pulling shots, I found the flow pattern is quite different between double and triple, although the taste from the triple seems to be better -- longer lasting crema and taste not as harsh.

Here is the triple shot :



Double shot :



I haven't had the LM double basket which I guess is ridgeless. Some other websites promote it as being able to make better espresso, like this one :

http://www.jetblackespresso.com.au/shop ... ridgeless/

Does it really help to fit in a tamper better, thus enabling a better shot?

Would a viscous liquid flow at a different rate through a filter comprised of simple cylindrical channels than it would through a filter comprised of channels that opened out like the bell of a trumpet, if the total effective filter hole diameter on the near (in) side of the filter were the same and everything else were identical?

timo888 wrote:Would a viscous liquid flow at a different rate through a filter comprised of simple cylindrical channels than it would through a filter comprised of channels that opened out like the bell of a trumpet, if the total effective filter hole diameter on the near (in) side of the filter were the same and everything else were identical?

If we called the image on the left example A, and the one on the right example B, I would guess that the expansion area in the bottom hole would allow larger bubbles to be formed in the crema, which would tend over time to merge and dissipate depending on the oily surface surfactants of the bean and roast in question.

In example B, I would expect a much more turbulent outflow in the area of each hole, and this would induce micro mixing and a more emulsifying effect of the gases in the outflow. As smaller bubbles would take longer to recombine I think a longer lasting crema would result.

This is only a guess based on basic physics, so YMMV.

Once again a long test period would be the only way to get a result, unless there was a obvious taste difference.

-Cecil

timo888 wrote:Would a viscous liquid flow at a different rate through a filter comprised of simple cylindrical channels than it would through a filter comprised of channels that opened out like the bell of a trumpet, if the total effective filter hole diameter on the near (in) side of the filter were the same and everything else were identical?

I don't think the liquid flow rate would be different from one or the other. I would say the way it comes out of the basket is quite different. One can see the difference in the videos posted by cksaurus (btw, thanks for it). In my opinion, the fact that the outside hole diameter in example A is larger than example B, makes the side of each hole closer together. This tends to collate the stream together and help to produce this beautiful streaming cone in the center of the screen.

Does it change the taste? I would say, not really. Until the barista's judgment is concentrated on the perfect streaming cone and makes some changes in distribution, dose, etc... When I compare both videos, I would say the double shot is more uniform than the triple. But cksaurus says the triple taste better!

A good looking shot does not a tasty shot make.

I have had some very nice looking shots that tasted like battery acid so dont get to caught up in how pretty the shot looks but concentrate on how it tastes.