The Berkey® red food coloring test is a simple assembly-verification test used with Black Berkey® Elements. It helps confirm that your Berkey® system has been assembled correctly and that water is passing through the filter elements rather than bypassing them through an improperly sealed opening.
When the system is correctly assembled and the Black Berkey® Elements are functioning as intended for this test, artificial red food coloring should not appear in the water collected beneath the elements.
Quick instructions: Prime the Black Berkey® Elements, remove any Berkey PF-2™ Elements, place a separate clean cup beneath each Black Berkey® Element, add 1/8 teaspoon (about 10 drops) of artificial red food coloring per gallon of system capacity to the upper chamber, and allow the water to filter through. The collected water should have no red or pink hue.
What Is the Berkey Red Food Coloring Test?
The red food coloring test is commonly used to verify the assembly of a Berkey® gravity-fed system equipped with Black Berkey® Elements.
The test can help identify situations in which untreated test water is bypassing an element because of an assembly issue such as:
- A loose wing nut
- An incorrectly positioned sealing washer
- An improperly sealed unused element hole
- An element that is not seated correctly
Testing each element over a separate cup also makes it easier to identify which installation position is responsible if red or pink water appears.
Important: Think of the red food coloring test primarily as an assembly and bypass verification test. A failed test does not automatically prove that a Black Berkey® Element is defective or exhausted. Check the installation and seals before reaching that conclusion.
Which Berkey Filters Can Be Tested With Red Food Coloring?
The red food coloring test discussed in this guide is specifically intended for Black Berkey® Elements.
Do not assume the same test should be used with other filter-element technologies.
In particular, this procedure is not intended for:
- Berkey Earth® Elements
- Ceramic filter elements
- Other filters not specifically designed for this test
- The Sport Berkey® Water Filter Bottle
If you are using a filter element other than Black Berkey® Elements, follow the instructions provided for that specific product.
What Kind of Red Food Coloring Should You Use?
Use artificial red food coloring appropriate for the Berkey red food coloring test.
McCormick's artificial red food coloring is one commonly recommended option.
Avoid substituting:
- Blue food coloring
- Green food coloring
- Yellow food coloring
- Natural red coloring made from beet juice
- Turmeric or other natural pigments
- Juice
- Drink mixes
- Other colored beverages
Natural colorings and products containing additional ingredients may behave differently and can produce misleading results.
Use red artificial food coloring only. Do not assume that another color or a naturally derived red coloring is an equivalent substitute for this test.
Before Performing the Test
Take a few minutes to prepare the system correctly before adding food coloring.
1. Prime the Black Berkey® Elements
The Black Berkey® Elements should be properly primed before performing the red food coloring test.
If the elements have recently been cleaned or have dried out, re-prime them before testing.
2. Empty Both Chambers
Begin with the upper and lower chambers empty.
Residual water containing food coloring from an earlier attempt can make the results more difficult to interpret.
3. Remove Berkey PF-2™ Elements
If Berkey PF-2™ Fluoride and Arsenic Reduction Elements are installed beneath the Black Berkey® Elements, remove them before performing the red food coloring test.
Do not allow the red food coloring solution to run through the PF-2™ Elements.
4. Check the Black Berkey® Element Installation
Before testing, make sure:
- The sealing washer is positioned on the filter stem inside the upper chamber.
- The wing nut is installed underneath the upper chamber.
- The wing nut is hand-tightened securely.
- Unused filter holes are properly sealed with the appropriate blocking plugs.
Do not use tools to tighten the wing nuts aggressively. They should be secure and snug by hand without overtightening.
How to Perform the Berkey Red Food Coloring Test
Step 1: Start With an Empty System
Empty both chambers. Remove any installed Berkey PF-2™ Elements before beginning the test.
Step 2: Place a Cup Under Each Black Berkey® Element
Instead of allowing all of the filtered water to mix together in the lower chamber, place a clean cup directly beneath each Black Berkey® Element.
This isolates the output from each element and makes troubleshooting much easier if one cup shows color.
Step 3: Add Water to the Upper Chamber
Add the appropriate amount of water to the upper chamber for the test.
Step 4: Add Artificial Red Food Coloring
Add 1/8 teaspoon, or approximately 10 drops, of artificial red food coloring for every gallon of system capacity.
Mix sufficiently so the test water has an even red appearance.
Step 5: Allow the Water to Filter
Let the colored water move through the Black Berkey® Elements and collect in the separate cups positioned beneath them.
Step 6: Inspect Each Cup
Look carefully at the water collected beneath each element.
Use good lighting and, if possible, inspect the cups against a white background so a faint pink tint is easier to see.
How to Read the Test Results
PASS: The water collected beneath each Black Berkey® Element is clear and shows no red or pink hue.
CHECK THE SYSTEM: If water collected beneath an element is red or pink, inspect the element installation, washer, wing nut, and blocking plugs before assuming the element itself has failed.
Separating the output into individual cups is particularly useful because it allows you to identify exactly which element position needs attention.
What to Check If Red or Pink Water Appears
A red or pink result can occur because test water is bypassing an element through an improperly sealed installation point.
Before assuming the element itself is the problem, check the following.
1. Are the Wing Nuts Secure?
Check the wing nut beneath each Black Berkey® Element.
It should be hand-tightened to a snug fit.
Do not use pliers, wrenches, or other tools to overtighten the wing nut. Excessive force can damage the stem or threads.
2. Is the Washer in the Correct Position?
The sealing washer should be located on the filter stem inside the upper chamber.
The wing nut is installed below the chamber.
If the washer and wing nut are both positioned underneath the upper chamber, the opening may not seal correctly and colored test water can bypass the filter.
3. Are Unused Holes Properly Sealed?
If your Berkey® system has unused element holes, confirm that the blocking plugs are correctly installed and tightly sealed.
Even a small leak around an unused hole can allow red water to enter the collection area, making it appear that a Black Berkey® Element failed the test.
4. Did You Use the Correct Food Coloring?
Verify that you used artificial red food coloring rather than another color or a natural food-coloring product.
Using the wrong coloring can make the test unreliable.
5. Was the Element Properly Primed?
If an element was recently installed, cleaned, or allowed to dry, make sure it has been properly primed.
If necessary, rinse and re-prime the element before repeating the test.
6. Could the Cup or Lower Chamber Still Contain Red Water?
The previous test solution can remain in a cup, chamber, or spigot, creating a false impression during the next test.
Rinse the collection cups thoroughly before retesting.
If you previously used the lower chamber to collect the test water, empty and rinse it and run clean water through the spigot before repeating the test.
How to Retest a Black Berkey® Element
If one position produces pink or red water:
- Empty the system completely.
- Remove the Black Berkey® Element in question.
- Inspect the stem and sealing surfaces.
- Rinse the element as appropriate.
- Re-prime the element if needed.
- Reinstall the washer inside the upper chamber.
- Hand-tighten the wing nut beneath the chamber.
- Verify that all unused holes are sealed.
- Use a clean cup beneath the individual element.
- Repeat the red food coloring test.
If the problem persists after correct assembly and retesting, further troubleshooting of the element may be appropriate.
Does a Failed Red Food Coloring Test Mean the Filter Is Exhausted?
Not automatically.
This is an important distinction.
A red or pink result can be caused by water bypassing the filter due to an installation or sealing issue.
Possible causes include:
- An incorrectly positioned washer
- A loose wing nut
- An improperly sealed blocking plug
- An installation problem
- An issue with the filter element itself
That is why the first step after seeing pink water should be to inspect and retest the assembly rather than immediately discarding the element.
Is the Red Food Coloring Test a Contaminant Test?
No.
The red food coloring test is not a substitute for laboratory water testing and does not indicate the concentration of individual contaminants in your drinking water.
A successful test demonstrates that the artificial red coloring used in the test does not appear in the collected water under the test conditions.
It should not be interpreted as proof that every possible substance has been removed from your source water.
For contaminant-specific information: Review the available performance information for the particular filter element being used rather than using the red food coloring test as a substitute for contaminant testing.
Do I Need to Perform the Test Every Few Months?
The red food coloring test is particularly useful when:
- Setting up Black Berkey® Elements
- Reinstalling elements after cleaning
- Troubleshooting possible internal bypass
- Checking assembly after disassembling and reassembling the system
- Investigating an unexpected change in system performance
Rather than relying on an arbitrary calendar interval, follow the current instructions provided for your Black Berkey® Elements and perform the test when assembly verification or troubleshooting is appropriate.
Why Must PF-2™ Elements Be Removed?
Berkey PF-2™ Fluoride and Arsenic Reduction Elements attach beneath compatible Black Berkey® Elements.
They must be removed before performing the red food coloring test.
Do not run the red test solution through PF-2™ Elements. Current warranty guidance specifically identifies performing the red food coloring test with PF-2™ Elements attached as something that can affect their six-month warranty.
If you use PF-2™ Elements, reinstall them only after completing the red food coloring test and returning the system to normal use.
Red Food Coloring Test Checklist
- Use Black Berkey® Elements only.
- Prime the elements before testing.
- Remove all PF-2™ Elements.
- Use artificial red food coloring.
- Do not substitute natural food coloring.
- Use approximately 1/8 teaspoon (10 drops) per gallon of system capacity.
- Place a separate clean cup beneath each element.
- Make sure washers are inside the upper chamber.
- Make sure wing nuts are snug by hand.
- Verify unused holes are properly plugged.
- Check each cup for any red or pink hue.
- If color appears, inspect the assembly and retest.
FAQ: Berkey Red Food Coloring Test
How much red food coloring should I use?
Use approximately 1/8 teaspoon (about 10 drops) of artificial red food coloring per gallon of system capacity.
Can I use natural red food coloring?
Natural coloring should not be substituted for the artificial red food coloring specified for this test. Natural products can contain ingredients that behave differently and may produce unreliable results.
Can I use blue or green food coloring?
No. Use the artificial red food coloring recommended for the Berkey red food coloring test.
Can I use beet juice instead?
No. Beet juice and other naturally derived coloring products are not appropriate substitutes for the specified artificial red food coloring.
Should I remove my PF-2™ Elements first?
Yes. Remove Berkey PF-2™ Fluoride and Arsenic Reduction Elements before conducting the red food coloring test.
Can I test the Sport Berkey® Bottle this way?
No. This red food coloring procedure is not recommended for the Sport Berkey® Water Filter Bottle.
Can I perform the red dye test on Berkey Earth® Elements?
No. This test is specifically associated with Black Berkey® Elements and should not be assumed to apply to Berkey Earth® Elements or other filter technologies.
What does it mean if the filtered water is pink?
First check the assembly. Inspect the washer position, wing nut, blocking plugs, and element installation. Rinse, re-prime if appropriate, reinstall, and retest before concluding that the element itself is responsible.
Does passing the red food coloring test prove my water contains no contaminants?
No. The test is an assembly-verification tool, not a laboratory analysis of your source water or a universal contaminant test.
Should I use the lower chamber to catch the test water?
Using separate cups beneath each Black Berkey® Element is more useful for troubleshooting because it allows you to evaluate the output from each element individually.
The Bottom Line
The Berkey red food coloring test is a simple way to verify the assembly of a Berkey® system equipped with Black Berkey® Elements.
The most important points are:
- Use only the appropriate artificial red food coloring.
- Use approximately 1/8 teaspoon (10 drops) per gallon of system capacity.
- Prime the Black Berkey® Elements before testing.
- Remove PF-2™ Elements before beginning.
- Place a separate cup beneath each Black Berkey® Element.
- Properly collected test water should show no red or pink hue.
- If color appears, check the system assembly and seals before assuming an element is defective.
The test is most useful when understood for what it is: a simple assembly-verification and troubleshooting tool, not a laboratory water-quality test.