On my GS3/AV , I was looking for a way to improve extraction. I talked to a technician at La Marzocco and also at Slayer. La Marzocco encouraged me to try 6 bar extractions, the Slayer tech talked about finer grinding and tamping with the weight of the tamp only. I adjusted my pump to 6 bar. I am using Black Cat espresso, weighing 17 gm in and getting about 23 gm out in 45-50 seconds. ( my machine has a 50 second limit). I use the La Marzocco 17 gm basket and a flat Espro tamp. I make sure the tamp is level and polish the shot. I get oily shots with tiger stripes on a fairly consistent basis.. much better than I used to get at 9 bar with 30 lb tamping.

occoffeeman wrote:On my GS3/AV , I was looking for a way to improve extraction. I talked to a technician at La Marzocco and also at Slayer. La Marzocco encouraged me to try 6 bar extractions, the Slayer tech talked about finer grinding and tamping with the weight of the tamp only. I adjusted my pump to 6 bar. I am using Black Cat espresso, weighing 17 gm in and getting about 23 gm out in 45-50 seconds. ( my machine has a 50 second limit). I use the La Marzocco 17 gm basket and a flat Espro tamp. I make sure the tamp is level and polish the shot. I get oily shots with tiger stripes on a fairly consistent basis.. much better than I used to get at 9 bar with 30 lb tamping.

What about the differences in taste , as opposed to visuals ?

The taste can range from sweet to salty with little to no bitterness. It does taste oily and concentrated.

Concentrated is more than likely a function of your brew ratio.. I guess these are things that are a positive for you . Personally i don't value oily as a descriptor but to each their own . I enjoy brews at 6 bar , but i tend to lower the temp a little and push extractions times a little longer for my given brew ratio ( 35- 40 second ) . I am brewing coffee's with lower brew ratios though .

I look for color then blonding. I notice more color coming out of the shot and later blonding which means improved extraction. Tiger striping is usually apparent. I tend to pull at 204 F. I find that the slower rate can cool the shot causing sourness. The higher temp compensates for that.

Ok , espresso porn is great but it needs to reflect in an improved taste, longer blonding or no but with that ratio is more than likely your nominally under extracting , but if you like the taste this doesn't matter .. personally salty and oily are not things i look for in espresso
Lower pressure shots have been around for a while and pre date this link , but it's worth a read
https://strivefortone.com/2016/05/18/th ... re-rehash/