If you’ve ever looked into measuring the acidity of foods and liquids, you’ve definitely heard of pH strips. These paper strips allow you to check how acidic or alkaline a certain solution is within minutes. Because of that, they’re very popular for academic, scientific, and also personal use.
But you may wonder if they’re actually accurate. After all, there’s limited space on the pH strips, and the pH scale goes from 1 to 14. So, are pH strips accurate?
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Are pH Strips Accurate?
Depending on the brand, pH strips have a varying degree of accuracy. Because of that, it depends on which ones you buy and what you need to test. What’s more, it’s not safe to consume foods or liquids that come into contact with the strips as they still contain some acids and bases, even though they’re weak.
It’s important to follow safety procedures and choose the safest options if you want to test the acidity of your food.
How do pH strips work?
PH strips work by indicating whether the liquid they come into contact with has a high or low pH level. To do that, they change their color based on the acidity or alkalinity of the sample.
Most often, if the indicator turns red, the pH is low, and if the indicator turns blue/green, the pH level is high. This happens because the sample reacts with the acids and bases present on the strips to give you the result.
Most pH papers usually go from 1 to 14, but there are also smaller scales that might be cheaper if you’re looking for something on the budget. Because of that, it’s a good idea to check how far the pH scale of your pH papers stretches to make sure that it’s suitable for whatever you want to check.
> A pH meter can help you determine the pH level of any food and drink you consume with very precise accuracy. Most of them are effortless to use and can help you follow a low-acid, mostly alkaline diet. We created a handy guide on how to buy the right pH meter.
How accurate are pH strips?
Generally, pH strips go from 1 (being the most acidic) to 14 (being the most alkaline). These usually get the least precise results as they have an accuracy of 1 pH. This means that if you’re looking for a more accurate measurement, it’s best to choose a pH meter as those are digital and more accurate.
PH strips don’t allow you to consume the foods or drinks you’re testing unless you use a separate sample. This is because they might be harmful once ingested, so they’re not too good for everyday food testing.
On the other hand, there are some pH strip versions that are more accurate, but they are more expensive. They’re also not as widely available, so again, your best bet might be purchasing a pH meter.
PH strips also lose their accuracy with age. So, you have to be particularly aware of when you’ve purchased the strips and opened them to ensure they’re still working properly.
More accurate pH strips go only as low as 0.5 pH. Because of that, they’re still not very precise for scientific or academic purposes. Even if you want to test the pH of your food at home, it might not suffice. As a result, pH strips are often used to estimate pH levels instead of giving you a precise reading.
This might be enough for some people, but if you’re looking for more accurate measurement forms, you might want to choose other options.
Another thing that might impact the accuracy of pH strips is contamination. If you’re testing a sample at home, you might have other liquids lying around, even if in small amounts. Most pH strips are extremely absorbent, which means that they might have already soaked up a sample, affecting your final reading.
To avoid this issue, make sure to test your food or liquid samples away from other potentially contaminating sources. It’s also important to store the pH strips in a dry place to ensure that they don’t get wet since you won’t be able to use them if that happens.
Are pH strips good for measuring food acidity?
Since you can’t consume the foods and liquids that come into contact with the pH strips, they don’t make for good measuring equipment for foods. This is because they still contain weak acids and bases to allow you to read the results.
These may be harmful to your health, so it’s important to avoid ingesting them. This also means that if you want to test your foods or drinks with pH strips, you should make a separate sample that you’ll insert the pH strip in to avoid any contamination.
Another thing to consider is that pH strips don’t allow you to test the acidity of soft-solid samples, such as meat, cheese, or fruit. This is because pH strips need a solution that soaks into the strip and reacts with the acids and bases.
While this might be possible with certain types of fruit, it won’t give you an accurate reading since fruit juices and raw fruit have different pH levels. The same goes for juices that might soak out from other food types.
Are pH strips toxic once expired?
Unless you consume them, pH strips aren’t toxic even if expired. The only thing that changes once they’re past their expiration date is their accuracy. This might be problematic since they’re already not as precise as other pH measuring equipment.
Sometimes their accuracy might even drop by two or three pH points, showing acidic samples as alkaline. Because of that, it’s a good idea to use your pH strips before their expiration date and discard the remaining ones to avoid mistakes in your readings.
PH strips aren’t particularly accurate, but it often depends on what you want to test and what your sample looks like. For example, if you need a very precise reading, it’s best to opt for a pH meter.
If you just want to get a general idea of how acidic or alkaline a sample is, then pH strips are your way to go. They’re relatively cheap and widely available, so they’re also a great start if you’re interested in testing acidity.