How to Make Homemade pH Paper Test Strips
Chop up some red cabbage., Add boiling water to your cabbage., Turn on the blender., Pour the mix through a strainer., Add isopropyl alcohol to your indicator solution., Pour the solution into a pan or bowl., Soak your paper in the indicator...
Step-by-Step Guide
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Step 1: Chop up some red cabbage.
You’ll need to chop about ¼ of a head of red cabbage and put it in a blender.
You will extract chemicals from the cabbage to coat your pH paper.
These chemicals are known as anthocyanins and are found in plants such as cabbage, roses, and berries.
Anthocyanins are purple under neutral conditions (pH
7.0) but they change color when exposed to an acid (pH <
7.0) or a base (pH>7.0).The same procedure can be followed using berries, roses, and other anthocyanin containing plants.
This does not work for green cabbage.
The same anthocyanins are not present in green cabbage. -
Step 2: Add boiling water to your cabbage.
You can boil the water on a stovetop or in the microwave, but either way you’ll need about 500 mL of water.
Pour the boiling water directly into the blender with the cabbage.
This will help draw the needed chemicals out of the cabbage., You need to blend the water and cabbage for best results.
Keep the mixture blending until the water is dark purple.
This color change indicates that you have successfully drawn the needed chemicals (anthocyanins) from the cabbage and dissolved them in the hot water.
You should allow the contents of the blender to cool for at least ten minutes before proceeding., You want to remove any pieces of cabbage from the indicator solution (colored water).
Filter paper will work in place of a strainer, but may take more time.
Once you have strained the indicator solution, you can throw away the cabbage pieces., Adding about 50 mL of isopropyl alcohol will protect your solution from bacterial growth.
The alcohol may start to alter the color of your solution.
If this happens, add vinegar until the solution goes back to dark purple., You want a container with a wide enough opening to dip your paper.
You should choose a container that is stain resistant, as you are pouring dyes into it.
Ceramic and glass are good options., Make sure to push the paper all the way to the bottom.
You want to cover all corners and edges of the paper.
It is a good idea to use gloves for this step., Find a location that is free of acidic or basic vapors.
The paper should be allowed to dry completely before proceeding.
Ideally, you will leave it overnight., This will allow you to test several different samples.
You can cut the strips any size you would like, but generally the length and width of your index finger is fine.
This will allow you to dip the strip into a sample without getting your fingers into the sample., You can test household solutions such as orange juice, water, and milk.
You can also mix up solutions for testing, e.g. mixing water and baking soda.
This will give you a wide range of samples to test., You should use an airtight container to store the strips until you use them.
This will protect them from environmental contamination such as acidic or basic gases.
It is also ideal not to leave them in direct sunlight, as this could result in bleaching over time. -
Step 3: Turn on the blender.
-
Step 4: Pour the mix through a strainer.
-
Step 5: Add isopropyl alcohol to your indicator solution.
-
Step 6: Pour the solution into a pan or bowl.
-
Step 7: Soak your paper in the indicator solution.
-
Step 8: Allow your paper to air dry on a towel.
-
Step 9: Cut the paper into strips.
-
Step 10: Use the strips to test the pH of different solutions.
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Step 11: Store the strips in cool dry place.
Detailed Guide
You’ll need to chop about ¼ of a head of red cabbage and put it in a blender.
You will extract chemicals from the cabbage to coat your pH paper.
These chemicals are known as anthocyanins and are found in plants such as cabbage, roses, and berries.
Anthocyanins are purple under neutral conditions (pH
7.0) but they change color when exposed to an acid (pH <
7.0) or a base (pH>7.0).The same procedure can be followed using berries, roses, and other anthocyanin containing plants.
This does not work for green cabbage.
The same anthocyanins are not present in green cabbage.
You can boil the water on a stovetop or in the microwave, but either way you’ll need about 500 mL of water.
Pour the boiling water directly into the blender with the cabbage.
This will help draw the needed chemicals out of the cabbage., You need to blend the water and cabbage for best results.
Keep the mixture blending until the water is dark purple.
This color change indicates that you have successfully drawn the needed chemicals (anthocyanins) from the cabbage and dissolved them in the hot water.
You should allow the contents of the blender to cool for at least ten minutes before proceeding., You want to remove any pieces of cabbage from the indicator solution (colored water).
Filter paper will work in place of a strainer, but may take more time.
Once you have strained the indicator solution, you can throw away the cabbage pieces., Adding about 50 mL of isopropyl alcohol will protect your solution from bacterial growth.
The alcohol may start to alter the color of your solution.
If this happens, add vinegar until the solution goes back to dark purple., You want a container with a wide enough opening to dip your paper.
You should choose a container that is stain resistant, as you are pouring dyes into it.
Ceramic and glass are good options., Make sure to push the paper all the way to the bottom.
You want to cover all corners and edges of the paper.
It is a good idea to use gloves for this step., Find a location that is free of acidic or basic vapors.
The paper should be allowed to dry completely before proceeding.
Ideally, you will leave it overnight., This will allow you to test several different samples.
You can cut the strips any size you would like, but generally the length and width of your index finger is fine.
This will allow you to dip the strip into a sample without getting your fingers into the sample., You can test household solutions such as orange juice, water, and milk.
You can also mix up solutions for testing, e.g. mixing water and baking soda.
This will give you a wide range of samples to test., You should use an airtight container to store the strips until you use them.
This will protect them from environmental contamination such as acidic or basic gases.
It is also ideal not to leave them in direct sunlight, as this could result in bleaching over time.
About the Author
Jean Moore
Specializes in breaking down complex home improvement topics into simple steps.
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