the espresso machine kind, of course ! ..

i keep 'choking' my gaggia because, well, i find it makes the most kickass coffee i have ever drank. it's like syrup, warm and barely any bitter.

however i'm always a little concerned when i see my 300$ beast choke the way it does; i always worry when i see no coffee come out after 5 seconds or when i look at that coffee, dripping one drop at a time, giving me barely half a small cup after 60 seconds. but boy is it good

so .. is this stuff bad for my machine ?

You describe a very tight ristretto. The machine should be designed to withstand the maximum pressure the vibratory pump can produce (usually 16 bar), so there's no reason to worry that it will damage your espresso machine. Technically the pump can overheat if it's run for more than 1 minute without a 1 minute rest, but that's a minor concern.