NYU chemistry professor Kent Kirshenbaum. Photo: Jeff Potter

Like many inquisitive scientists, Kent Kirshenbaum regularly scans the ingredient list of prepared foods to uncover the chemical composites lurking within. The substance that most recently piqued the New York University chemistry professor's curiosity is liquid smoke. "My immediate thought was that it was a horrible mix of chemicals," he told us.

After distilling the concentrated smoke and liquid mix (often sold at the grocery store by the bottle to enhance barbecue) down to its roots of water and more than 400 chemical compounds, the scientist (who in person comes across as one part Einstein, one part Malcolm Gladwell) learned that liquid smoke is actually "safer [for human ingestion] than untreated wood smoke."

Kirshenbaum discussed his discovery last week during a monthly gathering of the Experimental Cuisine Collective -- food nerds who love to make things like edible foam. We caught up with him to chat smoke, bongs and homemade liquid smoke.

What is liquid smoke?
Liquid smoke is very simply smoke in water. Smoke usually comes as a vapor, but there are ways to condense it and turn it into liquid and that liquid can then be carried in water.

How is it different from regular smoke?
Regular smoke is a vapor, and it is difficult to store.

In one healthier than the other?
It seems that the liquid smoke can be substantially healthier because there are carcinogenic compounds that can be removed. A lot of the carcinogenic compounds [found in direct smoke from charcoal or wood] do not dissolve. But by dissolving the compounds into water, they can be removed.

So, it's like a water bong?
Correct.

Who is using liquid smoke?
Liquid smoke is used by the majority of meat producers [to add] smoke flavor.

Can you give a couple of examples?
Typical beef jerky would be treated using a smoke product like a liquid smoke or powder smoke. I think a lot of people who are eating bacon or other smoked meats are getting it. I don't think it is necessarily something to be concerned about. I think this product has been studied and found to be safe.

Could someone make this home?
If they were determined, one could do it in their backyard or in their home. But you would have to be pretty determined and very patient. [To make liquid smoke, one would require a distillation apparatus, a lot of time and an open space. Slashfood does not recommend attempting this at home.]

Are people using the bottled version more at home?
Yeah, I think since the 1970s people have been using it more commonly. You can find a bunch of different products including flavors from different woods such as hickory, pecan and apple.

Why the 1970s?
Liquid smoke was invented in the 1880s, but efficient production began in the 1970s. Home cooks now use it routinely for marinating meats or to develop a smoky flavor in dips, that sort of thing.

How much does one need?
In my mind, the biggest danger is it is so easy to use too much. Typically a few drops is enough to give sufficient flavor to a pot of baked beans, for example. In the case of too many spices a little bit too much is annoying. In the case of liquid smoke it is noxious.

Noxious?
Yeah, it is extremely unpleasant. [As an alternative] use smoke spices like smoked salt or smoked paprika. Smoked salt is just salt used to trap the liquid components. It's just a matrix on which the smoke gets deposited into food.

Seems like a better alternative than outside grilling?
I don't think this will ever replace the backyard grill. But if you can't grill outside, if you are concerned about safety, if it's the middle of winter, this is a great way to replace that backyard.