Acidulated Water
Acidulated water is plain water with a small amount of acid, usually lemon juice or vinegar, mixed in. Cooks drop freshly cut fruits and vegetables into it to keep them from turning brown before they're cooked or served.
Why cut produce turns brown
Apples, pears, artichokes, avocados, bananas, celery root, and salsify contain an enzyme called polyphenol oxidase (PPO). When a knife breaks their cells, PPO meets oxygen and the fruit's natural phenolic compounds, turning them into brown pigments. This is enzymatic browning.
How acidulated water stops it
Acidulated water fights browning in three ways:
- It lowers pH. PPO works best near neutral, around pH 5–7. Dropping the surface pH toward 3–4 slows the enzyme dramatically (see pH in cooking).
- It blocks oxygen. Submerged produce has much less access to air.
- Vitamin C helps. Lemon juice contains ascorbic acid, which converts early browning compounds back to colourless forms before pigments build up.
Ratios
| Acid | Per 1 litre (4 cups) cold water |
|---|---|
| Fresh lemon juice | 2 tbsp (30 ml), or juice of ½–1 lemon |
| White or cider vinegar | 1 tbsp (15 ml) |
| Ascorbic acid powder | About ¼ tsp (about 1 g) |
Ascorbic acid powder (pure vitamin C) is the most effective and has almost no flavour, which makes it great for big batches of fruit you're freezing or canning.
How to use it
- Apples and pears: Slice straight into the bowl. Drain and pat dry before baking or serving.
- Artichokes: Rub cut surfaces with a lemon half as you trim, then hold the hearts in acidulated water until cooking.
- Celery root and salsify: Peel and cut directly into the water.
- Poaching: Adding lemon juice to the cooking water helps keep artichokes and cauliflower pale and bright.
When not to use it
- Potatoes. Cold water alone works. Acid can also prevent them from softening fully when cooked.
- Long soaks. After an hour or so, produce absorbs water and acid and can turn soggy and sour.
- Avocado and guacamole. Soaking ruins the texture. Instead, toss with lime juice and press plastic wrap directly onto the surface.
- Reactive pans. Don't hold acidulated water in bare aluminum or cast iron, which can discolour food and add a metallic taste.
Questions
What is the ratio for acidulated water?
Use about 2 tablespoons (30 ml) of lemon juice or 1 tablespoon (15 ml) of white vinegar per litre (4 cups) of cold water. One halved lemon squeezed into a large bowl of water works well too.
How long can apples sit in acidulated water?
Up to about an hour without losing much texture or picking up too much sourness. For longer holds, drain them, pat dry, and refrigerate covered.
Can I use vinegar instead of lemon juice?
Yes. White vinegar or cider vinegar works and is cheaper, but it leaves more of its flavour behind. Lemon juice also adds vitamin C, which helps prevent browning on its own.
Do potatoes need acidulated water?
No. Plain cold water is enough for cut potatoes because covering them keeps out the oxygen that browning needs. Acid can also make potatoes cook up firmer.