To reiterate that the pea blossoms won't make a blue beer, I experimented with the pH sensitivity to see if I could get a palatable blue beer.
I took a very pale, passionfruit sour ale I made and added the blossoms. It turned it a nice purple color and at first I added a baking soda (sodium...
I have heard that most transparent glass blocks a lot of UVA and UVB but still allows the visible spectrum to pass through. If glass is thick enough, it can pretty much absorb UV light completely, that's why Corona bottles are thicker (they weigh about 22 grams more than a stander brown bottle)...