A little reminder: Essential oils (common natural flavors) are considered unsuited for vaping because they arent water soluble and might accumulate in the lung, which could lead to lipid pneumonia. Thats why we (the vaping industry) use water soluble, artificial flavors and dont rely on naturally extracted ones. I see that an increasing amount of users starts to make their own flavor tinctures out of various foods and seasonings and thats a worrysome developement.

Essential oils from natural extractions probably aren't much of a concern.

But coffee contains diacetyl and you have no way of removing it. It's your decision but be aware that you're taking it. Article on recent clusters of bronchioitis found in coffee workers: http://m.jsonline.com/watchdog/watchdogreports/coffee-roasters-health-at-risk-from-chemical-compound-air-samples-suggest-b99505149z1-308183961.html

Yeah I did this a while ago, and I ended up with heaviness in my lungs, coughing, and flu-like symptoms. Coffee beans are terribly filthy and when grinded up contain tons of oils. Let alone the amount of Diacetyl in them. I didn't do any research before I did this, and since then won't vape any kind of extractions unless done by scientists in a lab. Just my experience

that bottle says glycerin (pg)... is it glycerin or is it propylene glycol? I'd worry about buying stuff from people who don't know the difference.

Interesting! I have some french coffee beans, anyone have a condensed milk flavor mixture?

sidebar. There is a diy extract post might check it out.