Look on the box to make sure these test strips cover the whole pH range. Some test strips only cover a portion of the pH scale. You need the color code on the box to accurately measure pH, so save the packaging after you open the box.
Rinse the cup with distilled water before filling it to make sure there are no contaminants that will throw off your results. Wear gloves and goggles if you don’t know what this liquid is. Acidic or alkaline liquids can burn your skin or eyes and require medical attention.
Don’t eat, drink, or brush your teeth for 30 minutes before doing this. These activities can affect your mouth pH.
When you pull the strip out, hold it above the cup for a few seconds so any excess liquid drips back in. Also wipe any remaining liquid on the inside of the cup. If the test strip doesn’t react at all, you may have a faulty batch. Try several and if you get no reaction, return them to the store.
If you’ve lost the test strip packaging, there are universal color codes available online. Search for one on the internet to conduct the test.
Most pharmacies carry containers of distilled water. There are also water companies that will deliver containers of purified water to your home.
Be careful when scooping food out of the processor. Avoid the blades so you don’t get cut.
If you’re testing a food item that came in liquid, also mix in some of that liquid. This gives you a comprehensive reading of the pH of the item.
When you remove the test strip, leave it over the cup for a few seconds to let any excess liquid drip off.
If you’ve lost the test strip packaging, there are universal color codes available online. Search for one on the internet to conduct the test.
Using red cabbage as a pH indicator is a popular classroom experiment, so school supply stores may also stock this.
Wear goggles during this step to protect your eyes from any splashes.
If the mixture is pink, the pH is 1-2. If the mixture is dark red, the pH is 3-4. If the mixture is violet, the pH is 5-7. If the mixture is blue, the pH is 8. If the mixture is blue-green, the pH is 9-10. If the mixture is green-yellow, the pH is 11-12.
If you’re testing several liquids, lay out several empty cups and fill each one with a different liquid. Label each cup so you remember which liquid is in each. Then pour the cabbage juice into each cup one at a time to test several at once.
