Answer

PTC is the most common taste test, and although its safety is sometimes questioned, our PTC test paper (HHE-250-100) is harmless - see the SDS.
PTC tastes bland, bitter or even vile depending on your genes. There is a single gene that codes for a protein found in our tongues. PTC will bind with the protein if it’s present, and you will certainly be able to taste it. However, if the protein is not present, the PTC will not bind and you won’t taste anything.
The ability to taste PTC is a dominant trait, so you’re in the majority if you’ve got it. ‘Supertasters’ taste these bitter compounds even more intensely.
‘Supertasters’ are more likely to find green vegetables bitter, like broccoli, Brussels sprouts, cabbage and kale.

Sodium Benzoate, Thiourea & Control test strips
A different pair of alleles determines the ability to taste Sodium Benzoate (HHE-250-150), so the taste results are different from PTC. Sodium Benzoate can taste salty, sweet, sour, bitter, or tasteless. Sodium Benzoate test strips can be used in conjunction with PTC to divide PTC tasters and non-tasters into subgroups.
Thiourea (HHE-250-200) is another taste test you can perform, and like PTC it is a bitter compound. The ability to taste PTC and Thiourea are genetically linked because they’re similar chemicals. However, this doesn’t mean you will have the same reaction to both. PTC and Thiourea are not identical, so some people may taste PTC but not Thiourea, or vice versa.
Control strips (HHE-250-250) – these non-impregnated strips are simply used as a comparison to the taste test strips, so that students can compare the effect of a plain paper strip on their tongues to one which is impregnated. Sometimes, just putting paper on the tongue could make some people think they can taste something, so the comparison should help to eliminate this.

Using multiple taste test strips, your participants will fall into groups/subgroups where you can then identify similar habits and traits among those participants.