What is Acid?
An acid is any food/substance that is below 7 on the pH scale which means anything that tastes sour to our tongues can be a source of acid. You may automatically think about foods like lemon or limes and their juices, vinegars, or wines. However, even fermented foods like different types of cheeses and dairy to sourdough bread to dark chocolate to tomatoes will leave a pleasant tang in the mouth. All of these foods are also acidic, but they all have a place in cooking.
Effects of Acid of Flavor
So how exactly does acid effect flavor? It all starts in the mouth! Think about drinking some delicious lemonade or sucking on a sour candy. What does your mouth do? It salivates. Out of five basic tastes, sour makes our mouths salivate the most. Why? Saliva actually balances out the acidity to avoid damage to our teeth. But the cooler thing is the more saliva that your mouth creates, the deeper the connection your mind makes to how delicious you believe the food is.
If you have watched any cooking shows, you will know that often the competitors will know exactly what they need to add their meals after tasting it as they go; they often add salt to enhance flavors, but they will add some type of acid to balance the flavors. Alone, acid isn’t delicious. Not many people enjoy drinking vinegar or sucking on a lemon as a source of food, but when you layer acid with the other tastes like sweet, salty, and savory, acid creates the balance that is needed to heighten the flavor of the foods.
Now Let’s Apply!
What is the best way to learn about how acid works in food? Application! Let’s make carne asada tacos. You will start with a tortilla, then layer down your carne asada, then pickled onions, other toppings like queso fresco, hot sauce, and top it off with fresh lime juice. How does acid play a part in these layers?
Depending on the type of cut of meat and what type of meat (red meat, poultry, or seafood), there are more connective tissues, collogen, and protein strands within the cut. Meats like carne asada have lots of coiled up protein strands that can become tougher when cooked with high heats; to avoid that, we want to denature, or loosen, the strands with acid (often both citrus and vinegar). When you denature protein, you tenderize the meat, that way when you add heat to the meat, you don’t create a tough piece of meat to ruin your taco. This process is often called marinating. The longer the marinating process is, the more flavor you infuse into the cut of meat and the more tender your cut of meat will become by the time you add heat to cook.
Pickled red onions
Acids like vinegar play a major role when you pickle ingredients like red onions. Pickling is the “process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar”. Vinegar helps red and purple produce retain their colors while they destroy bright green colors to create dull browns; so, when you pickle red onions with hot vinegar, your onions become a more vibrant red/purple color after you are done pickling. Acid doesn’t just change the color, but also the texture of foods as well. So, the onions go from crunchy to soft and tender after being pickled with vinegars.
Though queso fresco is about a 6.7 on the pH level after it is made, it is still less than 7 on the pH scale, making it an acidic food. But it’s the process on how to make homemade queso fresco that acids really play a major role. To make queso fresco you need: whole milk, white vinegar, apple cider vinegar, and salt. Those vinegars are what break up the milk proteins to become curds and whey. You drain the whey through a cheesecloth and keep those curds. Those curds then are molded together to create the disc of cheese that you know of when you think of cheeses.
Hot sauce can be considered spicy first, but when you really think about it, what is hot sauce made from? Fermented peppers (chili, jalapeño, etc.), salt, garlic, water, and a type of vinegar. That vinegar is the acid to balance the heat from the peppers, and the process of fermentation furthers that process of acidity.
The final bite
Though acid played a role in most of our taco ingredient layers, when you take a bite of your taco, your face doesn’t create that classic sour face. That’s because you used acid properly to balance your other ingredients and flavors, and not over powering the other tastes; that’s the key of making yummy food- know how to use acids properly to enhance your experience.