The Cocktail College Podcast: The Ultimate Guide to Acid-Adjusting

On the very first “Techniques” episode of “Cocktail College,” host Tim McKirdy explores how to acid-adjust cocktails. He is joined by NYC-based bartender and Solid Wiggles founder Jack Schramm, who uses his past experiences at NYC’s now shuttered Booker and Dax and Existing Conditions to guide aspiring bartenders who may be new to the technique.

How does acid-adjusting make for a more sustainable bar program? How, exactly, do bartenders alter the acidity of fresh citrus in their cocktails? And is there a way for home connoisseurs to do this? Tune in for the answers to these questions and more.

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Tim McKirdy: Welcome to VinePair’s “Cocktail College,” I’m your host, Tim McKirdy. Today, we are joined by a friend of the show, Jack Schramm. We’re kicking off what is — I’m very excited to announce — our inaugural “Techniques” episode. If you’ve listened to Jack’s appearance with the Paloma, you’ll know that this guy is absolutely ideal to discuss techniques with. If you haven’t, stop right now, go back, and listen to the Paloma episode. Jack, let’s kick it off again. How’s it going?

Jack Schramm: Great, Tim. Thank you so much for having me back. I’m thrilled to chat about techniques — great and small. Let’s get right into it.

T: Amazing. So we’re going to get into today’s topic. The first one we’re exploring is acid-adjusting. I think that’s a term that most of our listeners will have become more familiar with in recent years. I didn’t tell you this before we recorded, but you were the first person that actually introduced that to me IRL — in real life.

J: Wow.

T: I think it was at an event at Katana Kitten where there’s a couple of different bars bartending there. It was for a Shochu brand.

J: Yes.

T: That was very fun; we were chatting about it then. That was the first exposure I got to it. But like I said, this is something that’s becoming more mainstream. More bars are adopting it around the country. I want to get into that and learn all about it. Let’s get into it. First question, what is acid- adjusting? And who popularized this? Where did it start? Is this a technique that has its genesis in the bar movement?

J: This is a Dave Arnold technique. This is one of his ridiculous creations where he saw a problem that needed solving in the bar, and found a way to solve it. The problem was that bars are wasting a ridiculous amount of oranges because they use them for peels, and orange juice is basically useless in cocktails. Orange juice, specifically as an ingredient, is too sweet and flabby. The one orange juice classic that everybody thinks about is the Blood and Sand, which is basically the worst cocktail of all time. It’s right up there with Aviation. Come at me, I don’t care. Those are both terrible drinks.

T: Crème de Violette?

J: Oh my God; why do you want to taste potpourri? You don’t have to drink that.

T: The less said, the better.

J: Nobody’s making you drink that. Orange juice isn’t a good cocktail ingredient on its own, specifically because it’s so low in acid. That said, there are some varieties of sour oranges that are awesome in cocktails, but that’s not the variety of orange that you’re getting every day at your bar to make twists. So you’ve got all of this excess stock of fruit. The same goes for grapefruit twists. You’re using them for drinks, but then you’ve got all these grapefruits. What are you going to do with that juice? What are you going to do with this orange juice? I think that a lot of people hear “acid-adjusting” and ask, “Why are you adding more acid to lemon and lime juice?” No, I’m going to stop you right there. We’re not. That’s not what it’s designed to do. Lemon and lime are great in cocktails because they sit at 6 percent titratable acidity. A lot of people like to talk about pH, because that is the scientific measure of either how strong the acidity or how basic a liquid is. But it doesn’t tell you anything about how the liquid will taste in your mouth. The way to measure that is with titratable acidity, which is very similar to Brix and the way that Brix is the amount of dissolved sugar in a given solution. Titratable acidity is the amount of dissolved acid in a given solution. Lemon juice is 6 percent titratable acidity, and it’s all citric acid. Lime juice is 6 percent titratable acidity, but it’s a blend of citric and malic. It’s 4 percent citric and 2 percent malic acid.

T: For example, in a 100-grams solution, you would have 4 grams of pure citric acid and 2 grams of malic acid.

J: Exactly. In a total of 100 grams of solution. The thing that is great about those numbers, that 6 percent number, is that basic balance for most human beings is equal parts of a 6 percent titratable acidity juice and a 50 Brix syrup are going to balance.

T: They’re going to taste balanced.

J: Exactly. That’s why you see two, three-quarter, three-quarter as the jumping off point for every sour-style cocktail. It’s 2 ounces of spirit, three-quarters ounce of citrus, and three-quarters ounce of simple syrup. Some drinks need a little more acidity; some drinks need the sugar cut back. Whatever you need to do. But that’s such a great jumping off point for most people and for most drinks. That’s the math that makes it work. Orange juice is only around 1 percent acid, so it’s super mild on the acidity front. Thus, it’s not great as the primary acid component of a cocktail. But what if it could be? What if you could change the acid profile so that it’s the same as lemon or lime? The short answer is, you absolutely can. It’s as simple as adding enough citric and malic acid until it’s the same profile as lime juice. For a kilo of orange juice, you want to add 32 grams of citric acid and 22 grams of malic acid. And that turns it into lime acid-adjusted orange juice.

T: What about these ingredients, then? We’re working with acid here. Are these things that I should be worried about? Are these things I need to order from a specialist supplier? What are we talking about?

J: If you’re in New York, you can go to Kalustyan’s, and they’ll have them upstairs in the back in the acid powders section. Citric and malic are the primary flavor acids that you’re tasting in citrus juices, so those are the ones to look for immediately. You can find them on Amazon. If you’re looking for a large supply for a bar, is an incredible resource for acid powders, because you can get it anywhere from half-pound all the way up to around 10 kilos. You can get a big box of citric acid. That’s what we did at Existing Conditions because we use it just about every single day. It’s not going to go bad; it’s literally powdered acid. It’s the same consistency as granulated sugar. Store it in a labeled cambro and it’s good forever. You don’t have to worry about it as long as you keep it in a cool, dry place. So, those are the acids to buy. You can get them on Amazon, If you have a specialty food store, you’ll sometimes see it labeled as lemon salt. I think Duals Specialty has since switched over to saying citric acid on their labeling, but I’ve seen it in stores as lemon salt — that usually just means citric acid. If you’re thinking about what the flavor profile is of the pure acid, the coating on sour candies like Sour Patch Kids is a blend of citric acid and granulated sugar.

T: Interesting.

J: That’s what’s on the outside of those. That’s what that flavor is. So you know what it tastes like. I often hear people say, “Well, I just feel like this tastes chemically or it tastes artificial.” OK, but that doesn’t mean that it doesn’t also taste delicious. There’s a lot of people equating freshness with the word “natural.” It has no real definition when it comes to food products. If you are able to use a culinary technique as simple as dissolving something — you’ll dissolve sugar into water to make simple syrup — why not dissolve some citric and malic acid into orange juice to make it a palatable ingredient in cocktails that is really exciting and incredibly delicious? Because you can use the flavor of oranges, but with the acidity of lime.

T: You mentioned that lemon would be citric acid and lime is a blend of the two. What’s the consideration, then, when you do approach something like orange juice or grapefruit? Beyond trying to hit that percentage, how do you know which profile you’re going for?

J: At both Booker and Dax and at Existing Conditions, the two acid adjusted juices that were the staples were lime acid-adjusted orange and lemon acid-adjusted grapefruit. There wasn’t necessarily any specific reason for that, other than the drinks that we tried with those two flavor profiles were the ones that we were the happiest with. When you think about lime juice, you think more tropical. And orange is often a component in some of these tropical drinks. If you can just eliminate the lime from that, you can focus even more on the spirit or the modifier then you would need to if you have to use three-quarters of an ounce of orange juice and three-quarters of an ounce of lime juice. You’ve now got an ounce and a half of juice product and a build that could have been 3 to 3 and a half ounces and now you’re pushing it closer to that 4-and-a-half or 5-ounce big monstrosity that won’t fit in a coupe glass. So that’s the consideration. With lemon juice, you often think of more pristine-style cocktails, like your Tom Collins or a classic sour. Something about grapefruit really lends itself well to that style of drink.

T: It seems more citrusy naturally, I guess. Are they all citrus fruits? But it does seem more like that zesty, lemony idea works with the grapefruit. What about some examples, therefore, of how you’ve deployed those ingredients in the past? Can you give us some examples?

J: Absolutely. The first drink I ever put on any menu at any bar, I was still a bar back at Booker and Dax. Dave Arnold said, “Everyone is participating in this competition. Everyone who works here, come up with a drink that has three ingredients, and the winner gets the drink on the menu.” We already had milk-washed white rum. It was just Flor de Cana 4 Year, that was the rum at the time. It was for a drink called the Dr. J., which was acid-adjusted orange, simple syrup, vanilla tincture, and milk-washed rum. So it was basically the flavors of an Orange Julius with the serving style of a Daiquiri. It’s an incredibly delicious cocktail. I definitely aped that drink a little bit. I removed the vanilla and swapped the simple syrup for pineapple syrup. I was inspired by the Dole pineapple orange juice drink. I love pine-orange-strawberry or passion-orange-guava, this blend of orange juice as a base plus tropical flavors. So I was like, “Oh, I’ll just swap this for 50 Brix, pineapple syrup, acid-adjusted orange, and milk-washed rum. And it became this drink, the Tropical Thunder, that is super delicious and very clean and has a straightforward flavor profile. It’s basically a pineapple orange Daiquiri. There’s nothing wrong with that, but you’re not getting lost with an ounce of orange juice and an ounce of pineapple juice and three-quarters of an ounce of lime juice, plus a half-ounce of simple syrup. It just condenses everything into this neat package so you can focus on rum, pineapple, and orange, but it has the acid profile that you’re looking for out of a shaken cocktail.

T: Amazing. Obviously, there are a few ingredients in there that do require some extra preparation. Say someone was going out after listening to this, they buy some citric and they buy some malic. What’s a classic cocktail that they could quite easily reimagine using only this new technique that we’re incorporating?

J: Don’t try to take a classic cocktail, necessarily, and just sub in an acid-adjusted juice, because it’s not going to be greater than the existing drink. There’s a reason that the Tom Collins is so delicious. It is this ultra-pristine lemon and gin situation. You can swap in grapefruit and it’s still going to taste good, but it’s just not a Collins anymore. It sort of is this weird, uncanny valley at this point. I think this is why a lot of people don’t like, or disagree with, acid-adjusting conceptually. Because they’re like, “Oh, this is just stupid, it’s just making worse drinks.” But I would encourage you to take fresh grapefruit juice, add 40 grams of citric acid per kilo. We would also do it, sometimes, per liter if we were moving fast. It’s almost exactly the same. For water, a milliliter is a gram. For the juice, weigh it, measure it. It’s not quite spot on, but it’s close enough for this figure. So a kilo of juice and 40 grams of citric acid is going to yield lemon acid grapefruit. And I would encourage you to just make a sour with aquavit, acid-adjusted grapefruit and simple syrup. Taste that drink and tell me what you think. I think it’s the greatest example of a three-ingredient sour that exists. Something about the way that caraway and grapefruit play together is so insanely delicious. If you’re looking for a specific brand, I really like Linie. I like the aged Linie aquavit, that’s my personal favorite. It also works the best in most cocktail aquavit applications, but there’s plenty of great domestic aquavits as well. Svöl from Brooklyn is really lovely, either their Swedish or Danish. It works great in this cocktail. I’ve had it with Krogstad, and it tastes great. Whatever aquavit is available to me, I’m happy to drink it with acid-adjusted grapefruit and a little bit of simple syrup.

T: That sounds amazing. And that’s two, three-quarter, three-quarter?

J: Yeah, start there. I like to do scant one acid grapefruit, not all the way up to a full ounce, but I definitely like it a little bit higher-acid. I drink Daiquiris two-one — three-quarter, one lime — so I’m definitely more on the big, bold, juicy, high-acid flavor profile. Dave Arnold drinks Daiquiris half-half, which is crazy to me. So a half-ounce lime, half-ounce simple syrup, which kind of blows my mind. He’s like, “I’m old. I don’t need all this.” OK, cool, man.

The Cocktail College Podcast: The Ultimate Guide to Acid-Adjusting

T: Very nice. You’ve probably highlighted some of them, but would you have any hard and fast rules for bartenders, as to when they should be employing this technique? We’ve spoken about the general idea of not going too crazy, don’t overthink it. But when should you be employing this technique?

J: When you’re approaching a cocktail and realizing that you’re adding a lot of juice to it, and you’ve got a drink that’s losing the base spirit behind this wall of juices, try acid-adjusting. It’s not about adding an extra ingredient. That’s the other thing that people get caught up on. They’re like, “Oh, you’re just adding a bunch of nonsense to something that’s already perfectly good.” Well, we’re actually adding this stuff so that we can take other things away. Ultimately, it’s addition by subtraction. It’s cleaning up the flavors. It’s taking a drink that would have been five ingredients and turning it into what is essentially a three-ingredient cocktail. We just doctored a couple of the ingredients beforehand.

T: That’s wonderful; I think that’s a great way to sum it up there. You spoke about weighing. Are there any specific tools or things that really help with this process? And also, if I acid-adjust some grapefruit juice, what are we talking about in terms of shelf life? Does the addition of acid change that at all?

J: You need a scale, that’s non-negotiable. If you’ve got a crazy grocer scale, that’s awesome. But I would say a digital scale is going to be the easiest for you. You also need resealable containers. We would just do it in the container that we were going to store the juice in at the bar. That’s what we would acid-adjust in. Or in a cambro — a big bucket — and just stir it with a whisk. There’s no need to heat it up and have to cook this. The one circumstance, when something has been cooked, we will acid-adjust. This is another situation where people are like, “He’s acid-adjusting lemon and lime. It’s so dumb.” The one circumstance where it makes sense to do that is when you’re making a cordial. When you’re adding a bunch of sugar to something that’s acidic, you’re changing the quantity of acid in the solution. So if you’re going to make, let’s say, a 50 Brix clarified lime cordial, you may want to add some citric and malic acid to that to bring it back to the same acidity as lime juice so that it balances. It’s like using lime juice and simple syrup rather than sweetened lime juice.

T: If folks want an example of that and they haven’t heard it, I would urge them to listen to the episode with Toby Cecchini that we had on discussing his Gimlet, because he even uses that. He went down this path to rediscover the lime cordial, but he still adds fresh lime juice in his build, I believe. And this gets rid of that.

J: Even if I’m using a cordial, I still like to bolster it with fresh lime. Definitely if I’m going to do a shaken drink, just because of the texture and that bitter pithiness that you can sometimes lose in the cordial process. When you’re cooking a cordial, I highly recommend adding some peels from whatever citrus you’re making the cordial out of, just so that it extracts some of that bitter, pithy flavor that’s often lost.

T: Amazing. Do you have any other thoughts or any other advice here on acid-adjusting or things that you want to bring up yourself? Are there other applications that you’ve used it for?

J: Sure. We spoke about it off the air previously, but one of my cocktails that I’m the most proud of that I ever created started with that backbone of aquavit and acid-adjusted grapefruit. It was a drink from the Existing Conditions menu called the Helicopter. It was one ounce of milk-washed Linie Aquavit, one ounce of acid-adjusted grapefruit juice, three-quarters ounce of Cynar, and three- quarters of an ounce of Aperol with five drops of saline solution. It’s a relatively simple four-ingredient cocktail: shaken up, coupe, no garnish. Obviously, there’s something acid-adjusted and there’s something milk washed. There’s some work that went into it. I’d be happy to come back and talk about milk-washing.

T: I was going to say, we haven’t got into that yet, but if you can give us one sentence on why someone would be milk-washing.

J: Sure, milk-washing is a process of altering just the spirit. It’s not the same as making a Milk Punch. It’s a different thing, like how milk clarification is one thing and milk-washing is a different thing entirely. But the idea is the same, where you’re adding milk to a spirit, breaking the milk into curds with citric acid, and then filtering those curds out either through a super bag or, in our case, a centrifuge. What that yields you is a spirit that has some flavors stripped away. Like, if you milk-wash bourbon, you’ll notice that you stripped away a lot of wood. If you milk-wash a tea-infused vodka, you’ll notice that you’ve stripped away all the tannins, and it’s going to make a really delicious shaken cocktail. That’s another cool technique with milk-washing. What you end up with is a spirit that has whey protein left in it. When you shake something that’s rich in proteins, it ends up leaving a super-frothy, foamy head on top. It’s why egg whites work as a foaming agent. It’s why aquafaba works as a foaming agent. It’s why pineapple juice foams like crazy and honey is super foamy. It’s all that protein, and you can get that without adding any ingredient specifically to the drink. You can just have this milk-washed spirit. One note on milk-washing is that the protein denatures after five days, so try and use it quickly.

T: So that’s despite the fact that the spirit is the vessel for it?

J: The protein falls apart. I’m not a scientist. I probably used the word “denature” inappropriately. I don’t actually know what’s happening scientifically in this solution, but the frothiness isn’t as good after five days.

T: There you go. So you have that with the aquavit. Talk us through the rest of it there. You mentioned the ratio, but in terms of the intention of the drink?

J: Sure. I love that aquavit and acid grapefruit flavor profile. The Paper Plane is one of my favorite modern classics. Sam Ross just makes bangers, just good drinks. For those of you following along at home who may not be familiar, I’m so excited to introduce you to this drink. It’s equal parts — three-quarter, three-quarter, three-quarter, three-quarter — bourbon, lemon, Aperol, and Amaro Nonino. It’s a genius combination of flavors that work together. That was my template, basically, but I wanted it to have more of a punch of acid with the Nonino.

T: It’s a sweet-finishing amaro.

J: For sure, depending on the bourbon that you use.

T: That also has that perception of sweetness on the palate.

J: Perception of sweetness, or if you’re using a bonded spirit or an even higher-proof spirit, it can dry you out entirely. I wanted to have a good balance of acid and spirit and sweetness and bitterness, and I just found this. In a sense, it kind of tastes like a SweeTart, in a way that I really love. Candy tastes good.

T: There’s no denying it.

J: So this cocktail is sort of like the amaro-flavored SweeTart that also has this weird caraway thing that’s very thrilling.

T: Which is coming out of left field. But as you described before, it works so well with grapefruit.

J: Exactly.

T: I’ve read somewhere before that you also describe this as capturing the essence of grapefruit, the cocktail itself.

J: Because Aperol has that orange bitter, citrusy thing happening. Cynar has a little bit of that, too, more of that bitter grapefruit profile, like grapefruit pith or grapefruit peel profile. And the caraway in the aquavit is at the opposite side of the flavor wheel — that complementary flavor that works so beautifully with it. Marrying it all together is like a true expression of ultra-bright grapefruit.

T: To bring it all full circle and to come together here, if you were trying to make this cocktail with just fresh grapefruit juice, it just wouldn’t work. You wouldn’t be able to find the balance because of the acidity.

J: No, with those ingredients, you could not balance this drink. It would be flat, flabby, sweet, and very disappointing. Please don’t.

T: Amazing. Well, that’s been wonderful. Any final thoughts on acid-adjusting or things that people should be thinking about?

J: Just give it a try. Think about it not as a substitution, but as a new ingredient. The way that you would taste a new spirit or a new fruit that you were trying for the first time and try to come up with applications for lime-acid orange and lemon-acid grapefruit. The two most common examples — the two examples that I gave. Taste them for what they are individually and don’t try to just swap them in and out for lemon and lime. Taste it like it’s something new, and come up with new drinks using these new, exciting ingredients.

T: I love it. I’m imagining, as you described before as well, younger bartenders going out there discovering this technique. By all means, explore it. Have a lot of fun. I don’t want to see that, perhaps, on every single drink. If every single drink contains an acid-adjusted component, cool it guys.

J: Everything in moderation. You asked me earlier about shelf life, and I just wanted to touch on that. We were pretty dogmatic about shelf life at Existing Conditions and Booker and Dax. With lime and lemon juice, you had one day. You juiced it that day and you used it that day, and everything that you didn’t use that day would get dumped into a big bucket in the walk-in. And that at the end of the week, it would get clarified and turned into a shelf-stable cordial that we would then acid-adjust and use in stirred-style cocktails. We were trying to minimize as much waste as possible. For acid-adjusted juices, like orange and grapefruit, we would give ourselves another day. Even on the third day, we would taste it and make a decision. It usually got dumped that day. Or by the third day, we had just made the correct amount. I would say, whatever your current house amount of time that you find juice is acceptable, give yourself an extra day with this. There’s something about adding that much additional acid that’s acting as somewhat of a preservative — not in a weird, gross way. The flavor is just prominent for a little bit longer.

T: Like you said, sealed containers in the fridge. All these things are going to help. Amazing. Well, Jack, thank you so much for your time and thank you for giving us a science lesson today.

J: Of course, Tim. Any time. Happy to come on.

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Now, for the credits. “Cocktail College” is recorded and produced in New York City by myself and Keith Beavers, VinePair’s tastings director and all-around podcast guru. Of course, I want to give a huge shout-out to everyone on the VinePair team. Too many awesome people to mention. They know who they are. I want to give some credit here to Danielle Grinberg, art director at VinePair, for designing the awesome show logo. And listen to that music. That’s a Darbi Cicci original. Finally, thank you, listener, for making it this far and for giving this whole thing a purpose. Until next time.

Ed. note: This episode has been edited for length and clarity.