Well, some pummelos (possibly the original Indonesian pummelo that started the cross to create the hybrid we now know as the grapefruit) may have contained more Naringin, the chemical responsible for the bitter taste, than other pummelos. And, most of the commercial pummelos you can purchase at the store (frequently the Chandler, the most popular commercial pummelo variety) are bred for sweetness. So, as with anything else, there were traits that were preferred, and breeding was undertaken to promote those characteristics. At the time that grapefruits were becoming popular, that "bite" was desirable, so grapefruits have been bred to be a bit on the bitter side. That's the explanation in a nutshell. But, if you're not a fan of that bitter aftertaste, there are some really great grapefruit hybrids, plus a pummelo hybrid (that gets called a grapefruit, which it is not) are available that you might like. The most popular and most commercially available is the Oroblanco grapefruit hybrid. Also, it's "sister", the Melogold, not as easy to find, but equally if not better. And, the Cocktail grapefruit (which is not a grapefruit hybrid, but actually a pummelo hybrid) is my favorite, and the least bitter of all 3, very, very sweet, but still retains that "grapefruit" taste. Love it to pieces, have 3 Cocktail trees in my yard, in fact.

Patty S.

Patty-
Thank you, that is some great information. I'll look for some of those grapefriut. They usually just call them "red" or some other generic term. It's been years since I've tried a grapefriut so i'll pick up a couple of differnt varieties.

thank you

Well, they won't be called "red", those would be Rio Red, or Ruby Red grapefruits, and they are, indeed, 100% grapefruits. They're sweeter, as far as a full grapefruit cultivar goes, but not as sweet as an Oroblanco. They will be sold as "Oroblanco", not "red", "white", or anything else. So, watch for "Oroblanco".

Patty S.

Here is a link that might be useful: UC Riverside Citrus Variety Collection: Oroblanco Grapefruit Hybrid