I’m so passionate about coffee my girlfriend is a sack of beans

Well if it was Starbucks I would say “My passion for coffee is irrelevant because my passion for the people drinking the coffee shines through much clearer”
Because at the end of the day you don’t have to like coffee to give excellent customer service

What I've heard is that your experience at Starbucks is basically not relevant at all. We're the fast food of coffee and it doesn't compare whatsoever. So, I would actually *downplay* your Starbucks experience and acknowledge that you might have bad coffee habits from your time with them.

Basically, let them know you know you're a beginner and don't expect anything you know to translate.

Give em a story. 'well, ever since I was a kid I would go with my parents to a coffee shop, I can always imagine the smell of the beans, it reminds me of family time, etc, etc.,
With this, you could work in an appreciation for customer service as well if you wanted. 'it gives me such good memories that I want to be able to create those for others' or some bullshit.
Sure, it sounds cheesy as heck, but put it in your own words and I guarantee they'll love it!😂

I would say I’m very passionate about coffee, I enjoy learning different recipes and being able to express my passion by helping with recommendations and connecting with customers. Coffee has the ability to uplift many peoples days and it’s something I love to be apart of!! :) (be genuine and have some personal examples ready!)