Low pressure using double shot basket

Beginner and pro baristas share tips and tricks.
RaisingArizona

#1: Post by RaisingArizona »

Greetings,

Just jumped into home barista. Was using Gaggia super automatic machine for last few years and just got a new Breville dual boiler semi-auto as wanted more control

Been experimenting with grind size etc. but have question about the pressure during the pull. Using the single wall basket for single shot, the pressure seems fine getting up to 9 bar. But using the single wall basket for double shot the pressure only gets to about 2 or 3 bar. Any thoughts?

Thanks

Steve

Jeff

#2: Post by Jeff »

"Grind finer" is perhaps the most common advice needed by newcomers to home espresso.

Edit: I'm assuming you've got a small and standard basket for single and double and you're having problems using the standard basket.

What grinder are you using?

Your should be shooting for 18 g in, 30-40 g out in the cup, in around 25-35 seconds. Not exact numbers, depending on coffee and your tastes, but a good ballpark to get close.

A gram scale with 0.1 g readability and repeatability and at least 500 g capacity is a good tool to have for every shot. They start around US$15

RaisingArizona

#3: Post by RaisingArizona »

Thanks for the reply.

I believe the grinder is pretty good. I have a Breville Smart Grinder Pro.

The machine is a Breville Dual Boiler BES920XL.

I have been trying various grind settings and results are pretty good with the single shot basket. By the way, the machine has four baskets. A single and a double non-pressurized basket and a single and a double pressurized basket. So far, using the non-pressurized baskets.

When I press the single shot button on the machine, it has a pre-infusion pressure of about 3 bar, then ramps up to 8 bar. The total pull time is 28 sec. Been experiments with different coffee beans between 14 and 18 g of coffee and with the result of 28 to 30 g of espresso. So far so good.

When I switch to the double shot basked, I use about 20 to 24 g of coffee and result in 36 to 40 g of espresso with the a pull time a bit longer than 30 sec ... like about 32 sec. When I press the double shot button, the pressure ramps to 3 to 4 bar and stays there. It does not ramp any higher.

If I press the manual button and hold, it ramps up to 9 bar pretty quickly and keeps it there until I release the button.

There is difference in the taste. And, I am not sure if the machine deliberately keeps pressure lower for double shot vs single. As I review online about ratios I find many guidelines from 1:1.5 to 1:2.5 (g in vs g out). I expect the ratio depends on personal preference and is influenced by the level of roast of the coffee, grind coarseness, water temp, etc.

Steve

Jeff

#4: Post by Jeff »

The pressurized baskets are good for a dark drawer somewhere as you've got a decent grinder, from what I've read.

The grind for different baskets will be different. Especially if you're changing sizes!

16-18 g is a good starting point for a "double" basket, what most people here just call "a shot". It's different for some lever machines, but holds for most pump-driven machines.

Once you get close, Espresso 101: How to Adjust Dose and Grind Setting by Taste is a good read on how to adjust to change the taste. You can't get flavors out of the coffee that aren't there. Dark roasts won't have a lot of fruity flavors and light roasts won't have a lot of chocolate flavors, for example. You can swing the balance of what the coffee has to offer with dose, grind, ratio, and to a degree temperature.

DamianWarS

#5: Post by DamianWarS »

RaisingArizona wrote:Greetings,

Just jumped into home barista. Was using Gaggia super automatic machine for last few years and just got a new Breville dual boiler semi-auto as wanted more control

Been experimenting with grind size etc. but have question about the pressure during the pull. Using the single wall basket for single shot, the pressure seems fine getting up to 9 bar. But using the single wall basket for double shot the pressure only gets to about 2 or 3 bar. Any thoughts?

Thanks

Steve
pressure is based on the resistance from the puck and if there is little resistance then the pressure isn't going to get that high. To increase the resistance from the coffee typically the easiest answer is grind finer but you also may want to increase your dose. (just saw that your dose is fairly high at 20 to 24 g so maybe grind finer instead)

Traditional doses are 8 grams for a single and 16 grams for a double but modern examples typically are higher. It's best to use what your PF basket is designed for and if it's not written on the basket or in documentation then you can weight the empty PF then fill the basket and sweep the excess grinds off the top with your finger so it's flat (don't tamp) than weight it again... then round to the nearest number and that's probably your basket amount. So if it's 17.8g then you probably have an 18g basket.

Aim for a yeild that's twice the weight so 18g in would be 36g out and aim in the window of 25-30s. Adjust the grind finer for slower or coarser for quicker shots, but generally it sounds like you need to grind finer to increase the resistance/pressure.