That's funny.
Good manners are always the best way to approach anybody, (both side) but are we speaking about a species at extinction risk that must to be treated as a fragile object, or we are speaking about a normal person at work?
Anyway, i think that, if somebody does like his/her job, will be glad to share basic info, being skilled does not always means that you like what you do.

I have asked baristas for this sort of advice over the years. I just approach them politely and say something along the lines of that espresso was great, I wish I could duplicate that at home, I use the same beans that your shop does, do you mind sharing what your basic recipe was on that (grams in/out, time, etc.)?

More often than not, it's someone who is passionate about the coffee they will recognize you share the enthusiasm and are looking to improve. You're not challenging their expertise and you're not asking them for a full tutorial on how to make an espresso; just a few, pointed questions.

The best approach is to wait for a time when it's not busy and there's not a line out the door. There was one barista I really liked who I would ask questions from time to time. I knew better than to ask when they were slammed, but one time I came later in the day, after the rush, things were extremely slow, and he graciously told me if you ever have questions, these are the best times for me to chat.

Also, I like to leave a conspicuously generous tip to let them know I value the pro guidance and recognize that adds more value than just the drink they served me.

I learned to make espresso by talking to the owner and baristas at Spellas in Portland before I discovered HB. Several times a week I could stop for an espresso after dropping my kid off at school. Sometimes if they were busy it was just "hello" and "thank you, that was great." But when they weren't busy, the whole crew would often pitch in to answer my questions.

I found specific questions received the most useful responses. Instead of asking for their brew recipe, I'd ask how many grams they're using (14 usually). Then follow up with at what temperature? (197) and perhaps how many days post roast? (7 days). I could time the shots myself and see in the cups the approximate extraction ratio (ristretto, about 20 gr). As I got to know them they would share espresso lore and help me trouble shoot my shots; they took special pride in my compliment that I could come close but never quite equal their shots pulled on a Rancilio lever. And of course I'd tip reasonably and buy beans directly from the shop, not the local grocer, whenever I could.

Over years I've also had good success at other shops that also roasted their own beans. Shops that don't do their own roasting have a greater tendency--in my limited experience--to have baristas (and coffee) that is not as consistently good as shops that do their own roasting. Typically, I'll start the conversation after having a shot, then if I like it enough compliment the barista and buy a bag of beans. At that point I can check the bag for brewing info, and if it's lacking or incomplete then I ask the barista how to they get their best results.

Bottom line: courtesy, respect, repeat visits, and a genuine interest seemed to get me a lot of information.

My daughter is a barista. She trained at an Italian place and knows her way around the machine. However, she drinks tea rather than coffee. I don't think she would have all that much to say about coffee. If it's busy, she definitely doesn't want to talk to you.

As for owners of cafés being experts, i find that to be very much the exception. Most get the beans from somewhere else and contract out for service. Even in a decent café, the top barista may know more and the owner may rely on him or her.

I was excited to see a new café open in my out of the way neighborhood. They even roast their own beans. Then i talked to the owner who told me he was going for a *$ taste. I guess he knows what sells.

There are always exceptions, so here's a generalization. It's on us to choose quality cafes and to recognize a barista who's the equivalent of a good chef. If we treat that person with courtesy, we can have a relationship that both of us enjoy.

Way back when I used to commute to San Francisco via Ferry. This took me through the Ferry Building at the foot of Market Street where Blue Bottle Coffee was becoming a magnet for better coffee than the big chains. Their coffee was a revelation for me and others. I was a regular and would strike up conversations with the baristas when they weren't overwhelmed. One of the baristas there, whom I would visit with regularly, was a woman nicknamed "Charlie." She said I might be interested in Home-Barista.

There was a small shop near Redwood City, CA, where I later moved. There was one barista who was on top of his game. Once he pulled me a shot ground on a brew grinder. He didn't measure. It was delicious. We would regularly visit.

Phip wrote:I learned to make espresso by talking to the owner and baristas at Spellas in Portland before I discovered HB. Several times a week I could stop for an espresso after dropping my kid off at school. Sometimes if they were busy it was just "hello" and "thank you, that was great." But when they weren't busy, the whole crew would often pitch in to answer my questions. . . . . . . .

Andrea Spella has always been a gracious guy with me.

If the shop is not busy (re: long line at the 'Bucks where I would not go even to use the bathroom.. especially not that), and the person making my food product can't answer a few simple questions or does not know about what they are making I would go elsewhere and not return.

At one shop before I had any knowledge about espresso, the milk for my beverage was being stretched and I asked, "What is the thermometer for?"
He answered, "It's to make sure the milk gets hot enough to kill the bacteria."
If I only knew then what I know now. After reading this post to my wife before posting, she said, "You have to build your knowledge."
My reply was, "Some people show up to work without a tool kit."