TWIST not pressurizing
The most common question we are asked is, "Why won't my TWIST pressurize?". The most common answer is, "Have you checked to see if the small o-ring on the handle is still in place?".
This o-ring sits on top of the handle, right at the front, where it ensures the flow of gas from the handle to the water bowl doesn't escape. Unfortunately, if the o-ring has fallen out, as some of them do, then the gas will leak out, the water bowl won't pressurize, and there will be a distinct lack of good quality espresso coming through.
Fortunately, not all is lost, and certainly not all the o-rings. There's a small plastic bag included with every TWIST that has a full set of 4 (yes, four) small replacement o-rings. It also includes quite a few others, just in case.
The small o-ring can slip out when washing the handle, so please take care. Meanwhile, if you hear a gently hissing without the desired espresso, release the trigger, remove the water bowl, and check to see if that o-ring is in place.
Here's a picture with the original size and a blow-up for easier identification.

No 'spro? Check if the small o-ring on the main handle is in place. If not, there are spares in the bag.
If you need replacements, please contact us. The specifications
for this o-ring are:
1.5mm x 3.5mm ID, Buna-N, Shore A: 70
They can also be purchased online from McMaster-Carr. Search for part number
9262K517.