I just have to take note that the peak flavor of Chironja Grapefruit hybrid occurred between First to Second week of May.
Yesterday was my last sampling. The Chironja Grapefruit hybrid started out as with a tart grapefruit-like flavor starting from December, when it developed its bright yellow color, up to March when it stopped changing colors (neither fading nor getting deeper). Between March to April, it started to have some orange flavor, starting with just a hint and the tartness decreased. By May, the peels are really easy to take out, as easy as peeling a satsuma, only you have grapefruit sized fruits. The Flavor around May is more of a light tasting Navel orange, seedless (at least all of my fruits were), and just a small hint of grapefruit with no bitterness nor astringency at all. By second week of May, the pulp showed signs of drying but it still is juicy when you bite into it. It has slight non-overpowering sweetness and just a small hint of tartness, and very small hint of grapefruit flavor. It was simply very pleasant to munch, like a pummelo, only without the astringency. Due to the visible signs of drying of the pulps, we decided to finish all the fruits off yesterday, and we truly enjoyed it.
It is really worthwhile to know the peak flavor of your fruits and you can do it by continued sampling. But if you have fewer fruits, that would be very tricky. It is quite different location to location, even tree to tree within the same yard, and of course year to year. I take notes of performances from my yard to give me a good estimate for next year's harvest. Most data published are not exactly applicable here, but they give me an idea on how to adjust those estimates by comparing performances of my various cultivars with those of other places.
For example, we usually harvest most stone and pome fruits, one to two weeks later than those in the Central Valley. And my citruses are generally 3 to 12 weeks later compared to Southern California, in order to hit the best flavor. Compared to Benny, I harvest sometimes a month earlier than he does, but depends on variety. Likewise if you use my data shared here, and you happen to be outside our general area, you will have to calibrate my observations.
Most of my citrus cultivars are not discussed in detail in various publications as they are not commercially produced. So I try to share what I can learn from my trees. And if you do the same, we would get a much better picture of how a cultivar performs in various places. That is also why Millet, Laaz, I and others would be encouraging you to fill out your location in your member profile to contextualize specific problems, solutions or general information.
