I purchased an extra professional portafilter basket for back-to-back shots. Overall, it's very helpful.

However, I have found that the extra basket and the original one are not identical, which affects shot repeatability.

The baskets differ in weight. One weighs 79.6 grams and the other 80.4 grams.

This 1% difference is not a big issue, but I do notice a difference in pulling the shots. Given that back-to-back shots differ in other ways (probably due to the piston being hotter when pulling the second shot), I have also compared the two baskets not back-to-back but with some longer pause in between, and they do seem to respond slightly differently in terms of shot time, mostly. The difference is noticeable during pre-infusion already.

Has anyone else noticed this?

I also have two baskets for convenience when pulling two shots. I've always suspected that any variability was caused by first shot, second shot grinder differences, or perhaps one shot was tamped harder, or operator variability in lever pressure. Never thought of the baskets as a variable, but I am interested to see what others think. Unfortunately my Robot is in another location so I can't see if the baskets match.

There's a large number of variables with manual levers that will have more impact than <1g basket weight - I think you're looking for differences in the wrong place as espresso basket weight will commonly vary with standard manufacturing tolerances.

If the basket had varying numbers of or shapes of holes I can see the potential to affect taste, but such a small difference in weight will be negligible.

As you say piston temp varies with back to back shots, this can be seen in the tests Paul conducted on Cafelat's YouTube - although it will differ with different baskets since his were preheated by the previous shot. But is your puck prep (distribution, tamping pressure, etc), your water temp, pi time and pressure profile all constants too? These inadvertent differences are more likely to be culprits than a small change in basket weight.

Does one basket consistently run faster and slower than the other and if so, by how much under the same general conditions?

Jonk wrote:Interesting. Has the old basket seen a lot of use?

Both are under 6-months old. I purchased the second one shortly after the original one.

Allongedaze wrote:Does one basket consistently run faster and slower than the other and if so, by how much under the same general conditions?

I haven't marked them, and I don't remember which one is the original.

The first thing I noticed was the difference in weight and diameter, the latter being obvious since the same dosing cup fits differently in each. It fits comfortably in one and barely in the other.

This isn't a complaint or particularly problematic. The minor differences do affect the workflow ever-so-slightly. I haven't kept track of the differences closely enough to determine whether there are repeatable effects on taste, timing, etc.

I have read many times on this forum from people stating that the first shot and the second shot of the day, not from the robot, were quite different. Some of the suggestions were along the lines of temperature differences between the first shot, perhaps grinder retention, among others.

Do you alway use the baskets in the same order? "IF" so perhaps try reversing the order and see if things still remain the same. This could possibly help diagnose if it is the basket, or something else.

I have two professional Robot baskets and the weight differences between them are similar to yours. I have not noticed any differences in shot quality or speed, and have been able to pull repeatable shots. Prior to brewing I preheat the robot piston and portafilter using a pressurized basket.

You could probably test the flow of the baskets by filling them completely with water and look at the time it takes to empty. I will be surprised if the outcome will be different for different baskets.

esporfa wrote:I haven't marked them, and I don't remember which one is the original.

The first thing I noticed was the difference in weight and diameter, the latter being obvious since the same dosing cup fits differently in each. It fits comfortably in one and barely in the other.

This isn't a complaint or particularly problematic. The minor differences do affect the workflow ever-so-slightly. I haven't kept track of the differences closely enough to determine whether there are repeatable effects on taste, timing, etc.

The diameter difference is interesting, it may be worth measuring the bottom diameter and looking for differences in hole numbers or patterns.

As another reply has said, it is a good idea to mark one and test each basket's flow without coffee to get an idea of differences if any. It's a lot of effort but the more times you can run it then the better. Either that or just keep making coffee as usual and just record results and whether it's the larger or smaller one.