Acidity is a key component to skillful cooking. Chefs are always talking about how a splash of acidic vinegar is what elevates a dish. Michael Harlan Turkell has spent his entire career around chefs, first as a cook himself, and then as a photographer and writer. During the time it took write and research his new book, Acid Trip, he’s become an expert on vinegars. He travels the world to explore them, creates many different vinegar infusions, and makes his own vinegars at home. Contributor Shauna Sever talked with Michael about bringing this centuries-old ingredient into modern home kitchens. They were also happy to share recipes for Vinegar Butter Sauce and Vinegar Pie.

Shauna Sever: Tell us how your obsession with the world of vinegar came about.

Michael Harlan Turkell: I think the same way most people make vinegar the first time, by accidentally leaving a bottle of red wine out and open on the table. That snowballed into a couple other alcohols. I had a leftover quarter-keg of beer that I poured into a barrel, and it turned into the best malt vinegar I've ever had in my life.

SS: Definitely a happy accident.

MHT: It is. And now it's an absurd obsession.

Michael Harlan Turkell (Photo: Shannon Sturgis/Star Chefs)

SS: Your book reveals vinegar to be so much more versatile in the kitchen than we might realize. Can you tell us about some of its main functions in cooking and baking?

MHT: Vinegar is a flavor carrier. It's not just this overt thing that punches you in the chest and makes you cough. It is a vehicle for other flavors to comingle and coalesce. When you make a vinaigrette, with either 2-to-1 or 3-to-1 ratio of oil to vinegar, you're trying to express the nuances and aroma in the vinegar by carrying it in that fat. That carries over into a lot of cooking processes. It deglazes pans to pick up the fond, it stabilizes egg whites in meringue. It is an interesting part of cooking, because as overt as we think it is, it's actually about the balance and harmony in a lot of other cuisines.

SS: In baking, vinegar is used in many old-fashioned baking recipes to react with leavening agents.

MHT: Absolutely. That science experiment of baking soda and vinegar shooting up like a volcano is like what Irish soda bread is, using that as a faux leaven.

SS: One of the things that I found so fascinating in your book is that you chose to organize part of the book by different cuisines across the globe. Give us some examples of vinegars that are unique to certain places, and how they're used.

MHT: I'm going to go chronologically, like the book. First, I got to go to France, Italy, Austria, Japan, and back through North America. In France, there's a lot of butter, a lot of cream, and it's delicious because of those things. But those sauces have vinegar in them; they have some acidity to balance all that out. You find vinegar in béarnaise, hollandaise, and in most of the master sauces. But it's not necessarily the thing that we first think of as the primary ingredient.

Looking at Italy, I just got back from a trip in the Emilia-Romagna region, where balsamic is king. Balsamic is probably the most ubiquitous vinegar around the world now. However, the amount that's made for tradizionale – which is the original balsamic vinegar that wasn't exported to the other parts of the world until the 1970s – such a small amount is made that a lot of people haven't even experienced it. Seeing that vinegar in context, seeing that it's barely used as an application where you heat it up. Instead, it's on top of aged parmesan or strawberries, or maybe the accent of stuffed pasta.

Then in Austria, I think quite possibly the greatest vinegar maker in the world lives in Vienna. He is singular in that he makes vinegars from single ingredients: tomatoes, saffron, red pepper, trockenbeerenauslese. He makes these things that are linear and pure; I've never tasted a vinegar so expressive of its inherent self.

by Michael Harlan Turkell

SS: Then you have things like rice vinegars and rice wine vinegars in Asian cuisines.

MHT: This was another thing that I'd only really experienced by way of what you buy in the supermarket – Kikkoman, Mizkan, or Marukan rice vinegars. But when you taste a real rice vinegar, it's like taking a shot or a sip of sake for the first time. There is so much expression and terroir to it. Rice vinegar can be the same way. There isn't just acidity. There is flavor, which is dependent on what kind of rice they use, and how much it's polished down. On top of that, the traditional rice vinegar, komesu, is probably the gold standard of rice vinegars in Japan. There's akazu, a red vinegar made from the aged sake kasu, or sake lees. It literally turns almost black in hinoki wooden boxes before it's pressed. Kurosu is from the Kyushu province; it's black vinegar that's used more as a drinking vinegar than it is as something in culinary practices.

SS: That's fascinating. There are so many different flavors of vinegar. We know about things like tarragon vinegar, where you steep an herb in the vinegar. But what are some of the more scientific elements that give vinegars their distinct flavors?

MHT: Vinegar is nothing more than 4 to 6 percent acetic acid in solution, and that solution is water. Like with wine, there are a volatile esters, aromas that are carried within that solution. That's what you're tasting and smelling. When you make an infusion, you encapsulate whatever that aroma is in the solution, it pairs with acetic, and goes through that olfactory motion of tasting and smelling.

But vinegar is often a sensation before it's a flavor. You taste that on your palate, you have that feeling of brightness, of enlivening, it makes you salivate a little bit. That's when it hits. That's when the flavors get picked up. Like I said, vinegar is a carrier, but the thing that it initially does is open up your palate to be able to experience those flavors.

SS: If anyone's going to get us to make vinegar at home, it's you. Tell us what are some of the basic tools we need to get started.

MHT: First, you need a good juice. Vinegar is made from any starch that can convert into a sugar, then turn into an alcohol, and eventually become vinegar or acetic acid. You have to find one of those bases. Starches include grains and rices. Sugars include honey and cane. There are fruits and vegetables as well. You have to define what you want to make it out of, because you have to figure out what you’re going to use it for.

After that, it's kind of like any home brewing. You just need a kit that can carry that solution, and a vessel – I suggest glass, maybe a ceramic crock, wood if you're adventurous. There are a couple other tools. The first thing, if you're making your own alcohol, is a refractometer. It looks like a little clarinet, and it checks the brix, or the sugar content. The next thing you use is a hydrometer; it looks like a floating temperature gauge. It bobs up and down in a solution, and tells you what the potential ABV – or alcohol by volume – output is going to be. A litmus test called pH strips tell you the percentage of acidity in solution. Anywhere from 2.8 to about 3.4 is what you're aiming for. You dip one into your liquid. When when you take it out, it changes to a certain color; check on the color scale whether or not you're in that range. Aside from that, you’ll need time and patience.

Shauna Sever

Shauna Sever is the author of three cookbooks (Marshmallow Madness!, Pure Vanilla and Real Sweet). She is the voice behind the baking blog Piece of Cake. She's appeared on the Today show, Food Network, Home and Family, Serious Eats, Chow and Her writing and recipes have been featured in O, The Oprah Magazine, Food and Wine, Bon Appetit, Fine Cooking, Family Circle and USA Weekend.