pH values of common liquids
29 everyday substances from strongly acidic to strongly alkaline, sorted ascending - to put your own readings in context.
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A single reading says little - comparison is what makes it tangible. This table places common liquids on the pH scale, ascending from the strongest acid to the strongest alkali.
How these steps translate into ion concentrations is shown by the interactive pH scale.
The table
| Substance | pH value | Category | Note |
|---|---|---|---|
| Battery acid | 0.5–1.0 | Household & chemistry | Dilute sulphuric acid. |
| Gastric acid | 1.0–3.0 | Human body | Strongly acidic - dissolves food. |
| Lemon juice | 2.0–2.6 | Food & beverages | Citric acid determines the value. |
| Cola drinks | 2.4–2.6 | Food & beverages | Phosphoric acid as acidulant. |
| Household vinegar | 2.4–3.4 | Household & chemistry | Depending on acid content. |
| Wine | 3.0–4.0 | Food & beverages | White wine usually more acidic than red. |
| Orange juice | 3.3–4.2 | Food & beverages | Varies with variety and ripeness. |
| Sauerkraut | 3.4–3.6 | Food & beverages | Lactic fermentation lowers the value. |
| Beer | 4.0–4.6 | Food & beverages | Mash sits higher, at about 5.2-5.6. |
| Bog and blackwater | 4.0–6.0 | Water & nature | Humic substances lower the pH. |
| Tomato juice | 4.1–4.6 | Food & beverages | Borderline range for preservation. |
| Yoghurt | 4.3–4.5 | Food & beverages | Indicates the degree of fermentation. |
| Skin surface | 4.7–5.5 | Human body | The familiar acid mantle. |
| Coffee | 4.8–5.2 | Food & beverages | Roast and brewing method matter. |
| Rainwater | 5.0–5.6 | Water & nature | Dissolved CO₂ makes it slightly acidic. |
| Soft-water aquarium | 6.0–6.8 | Aquaristics | Discus, tetras, South America. |
| Fresh milk | 6.5–6.8 | Food & beverages | A falling value indicates spoilage. |
| Pure water (25 °C) | 7.0 | Water & nature | The neutral point of the scale. |
| Drinking water | 7.0–8.5 | Water & nature | In Germany usually 7.0-8.5. |
| Pool water (target) | 7.0–7.4 | Pool | Optimal range for chlorine action. |
| Human blood | 7.35–7.45 | Human body | Extremely tightly regulated. |
| Hard-water aquarium | 7.8–8.5 | Aquaristics | Malawi and Tanganyika cichlids. |
| Seawater | 8.0–8.4 | Water & nature | Reef aquariums follow this range. |
| Baking soda solution | 8.0–8.4 | Household & chemistry | Weakly alkaline. |
| Soap solution | 9.0–10.0 | Household & chemistry | Classic example of alkaline. |
| Detergent solution | 10.0–11.0 | Household & chemistry | Alkaline to dissolve fats better. |
| Ammonia solution | 11.0–11.5 | Household & chemistry | Component of cleaners. |
| Limewater | 12.4 | Household & chemistry | Saturated calcium hydroxide solution. |
| Caustic soda (drain cleaner) | 13.0–14.0 | Household & chemistry | Alkaline-error range of the electrode. |
Sorted by category
Food & beverages
- Lemon juice 2.0–2.6
- Cola drinks 2.4–2.6
- Wine 3.0–4.0
- Orange juice 3.3–4.2
- Sauerkraut 3.4–3.6
- Beer 4.0–4.6
- Tomato juice 4.1–4.6
- Yoghurt 4.3–4.5
- Coffee 4.8–5.2
- Fresh milk 6.5–6.8
Household & chemistry
- Battery acid 0.5–1.0
- Household vinegar 2.4–3.4
- Baking soda solution 8.0–8.4
- Soap solution 9.0–10.0
- Detergent solution 10.0–11.0
- Ammonia solution 11.0–11.5
- Limewater 12.4
- Caustic soda (drain cleaner) 13.0–14.0
Water & nature
- Bog and blackwater 4.0–6.0
- Rainwater 5.0–5.6
- Pure water (25 °C) 7.0
- Drinking water 7.0–8.5
- Seawater 8.0–8.4
Aquaristics
- Soft-water aquarium 6.0–6.8
- Hard-water aquarium 7.8–8.5
Pool
- Pool water (target) 7.0–7.4
Human body
- Gastric acid 1.0–3.0
- Skin surface 4.7–5.5
- Human blood 7.35–7.45
Why the values vary
The ranges given are guide values. The pH of a food depends on variety, ripeness, production and storage; for waters, temperature, dissolved CO₂ and carbonate hardness are added. For reliable statements the rule therefore remains: measure yourself, with a freshly calibrated electrode.
Measuring it yourself
Most substances in this table can be measured with an ordinary gel electrode. Two exceptions: solid and semi-solid samples such as cheese or meat need a spear-tip electrode, and strongly alkaline solutions from about pH 12 require low-alkaline-error special glass. Every measurement series starts with calibration.
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