Most fruits, fermented foods, and many popular beverages are acidic, with pH values well below the neutral mark of 7.0. The most acidic common foods are citrus fruits and vinegar, which can dip as low as pH 2.0. Understanding which foods are acidic matters for two practical reasons: protecting your tooth enamel and managing acid reflux.
How the pH Scale Applies to Food
The pH scale runs from 0 to 14. Anything below 7.0 is acidic, anything above is alkaline (basic), and 7.0 is neutral. The scale is logarithmic, meaning a food with a pH of 3.0 is ten times more acidic than one at pH 4.0. Most whole foods fall somewhere between pH 2.0 and pH 7.0, so nearly everything you eat is at least slightly acidic.
The FDA uses pH 4.6 as its dividing line between “acid” and “low-acid” foods. Foods at or below 4.6 are acidic enough to prevent the growth of dangerous bacteria like the one that causes botulism. This is the same threshold used in home canning to determine which foods need pressure processing.
The Most Acidic Foods by Category
Citrus Fruits
Citrus sits at the extreme end of food acidity. Lemon juice ranges from pH 2.0 to 2.6, and lime juice is nearly identical at pH 2.0 to 2.35. Grapefruit falls between 3.0 and 3.75, while whole Florida oranges land around 3.69 to 4.34. Orange juice is slightly more acidic than the whole fruit, typically ranging from pH 3.30 to 4.19.
Vinegar and Pickled Foods
White vinegar has a pH around 2.4 to 3.4, making it comparable to lemon juice. Any food pickled in vinegar, from cucumbers to onions, takes on a similarly acidic profile. Fermented foods like kimchi and sauerkraut also become highly acidic during production, as bacteria convert sugars into lactic acid. Regulatory standards require fermented foods to reach a pH of 4.6 or below to be considered safe.
Tomatoes
Tomatoes and tomato-based products are moderately acidic, generally falling between pH 3.5 and 4.7. The FDA actually singles out tomatoes in its food safety regulations because they sit right near the 4.6 threshold. Canned tomato sauce, salsa, and ketchup all fall in this range, which is one reason tomato-heavy meals are a common reflux trigger.
Berries and Stone Fruits
Cranberries, blueberries, and strawberries typically range from pH 2.5 to 3.5. Stone fruits like plums and cherries are slightly less acidic, usually between 3.0 and 4.0. Apples fall in the 3.3 to 4.0 range depending on variety, with green apples being more tart and more acidic.
Sodas and Other Beverages
Cola drinks are notably acidic, partly because they contain phosphoric acid as an additive. Most colas have a pH between 2.3 and 2.5, putting them on par with lemon juice. Coffee ranges from about pH 4.0 to 5.0, and wine typically falls between 3.0 and 4.0. Even sparkling water is mildly acidic (around pH 3.0 to 4.0) due to dissolved carbon dioxide.
Fermented Dairy
Yogurt has a pH around 4.0 to 4.6, and buttermilk is similar. Regular milk is only mildly acidic at about pH 6.5 to 6.8, while butter sits at 6.1 to 6.4. Aged cheeses vary widely but tend to be more acidic than fresh milk.
Foods That Are Less Acidic Than You’d Think
Beans and legumes are only mildly acidic to nearly neutral. Black beans measure pH 5.78 to 6.02, kidney beans range from 5.4 to 6.0, and garbanzo beans sit at 6.48 to 6.80. Tofu is actually slightly alkaline at pH 7.2. Most cooked vegetables, rice, and bread cluster in the 5.0 to 7.0 range, making them relatively gentle.
Bananas, melons, and cauliflower are considered alkaline foods despite being plant-based alongside their more acidic cousins. Fennel and nuts also fall on the alkaline side.
Acidic pH vs. Acid-Forming in Your Body
Here’s where it gets counterintuitive: a food’s pH in the kitchen doesn’t predict how it affects your body’s chemistry. Researchers measure something called the potential renal acid load (PRAL) to estimate whether a food makes your urine more acidic or more alkaline after digestion. Nearly all fruits and vegetables have a negative PRAL score, meaning they’re alkaline-forming in the body, even when they taste sour.
Raisins, for example, score -21 on the PRAL scale, making them one of the most alkaline-forming foods despite being acidic to the taste. Spinach scores -14, carrots -4.9, and even tomatoes come in at -3.1. On the other hand, meat, cheese, and grains tend to be acid-forming in the body despite having a relatively neutral kitchen pH. So if you’re thinking about acidity in terms of overall body chemistry, the picture flips: the foods that taste acidic are often the ones that push your system in the alkaline direction.
Why Acidic Foods Matter for Your Teeth
Tooth enamel starts dissolving at about pH 5.5. This threshold, known as the “critical pH,” has been studied since the 1940s. The exact point varies slightly depending on your saliva’s calcium and phosphate levels, but pH 5.5 is the widely accepted benchmark from the American Dental Association.
That means nearly every food in the “most acidic” categories above, from citrus and soda to wine and berries, falls well below the enamel danger zone. The risk isn’t from eating these foods occasionally. It comes from prolonged or frequent exposure: sipping lemon water throughout the day, nursing a soda for hours, or sucking on sour candies. Your saliva naturally neutralizes acid, but it needs time between exposures to do its job. Drinking acidic beverages through a straw and rinsing with plain water afterward both reduce contact time with your teeth.
Acidic Foods and Acid Reflux
If you deal with heartburn or gastroesophageal reflux, acidic foods can make symptoms worse by irritating an already-inflamed esophagus. Tomatoes, citrus, coffee, and carbonated drinks are among the most common triggers. The issue isn’t just pH, though. Fatty foods, chocolate, and alcohol can relax the muscular valve between your stomach and esophagus, allowing acid to splash upward regardless of what you ate.
Lower-acid alternatives that tend to be better tolerated include bananas, melons, cucumbers, celery, lettuce, and herbal teas like ginger tea. Nonfat milk can act as a temporary buffer against stomach acid, and low-fat yogurt offers similar soothing effects. Watermelon and broth-based soups are also gentle options that keep you hydrated without adding acidity.
One oddity worth noting: a small amount of lemon juice mixed with warm water and honey can actually have a neutralizing effect on stomach acid despite lemon’s extremely low pH. The dose and dilution matter, so this isn’t a green light to drink straight lemon juice if reflux is a problem for you.
Processed Foods With Hidden Acidity
Some processed foods are more acidic than their homemade equivalents because of added acids. Phosphoric acid (listed as E338 on ingredient labels) shows up in cola drinks, processed cheeses, baked goods like packaged cakes and biscuits, and some meat products. Certain plant-based milks also contain phosphate additives. These additions lower pH for flavor or preservation purposes, so a packaged version of a food may be significantly more acidic than the same dish made from scratch. Checking ingredient lists for phosphoric acid or any additive starting with “phosph-” is the quickest way to spot these.