Immediately after I make my green tea cookies they are bright green in color. I use a high quality matcha from one of the best tea shops in the city, since I don’t like the bitterness found in many cooking matchas (which are significantly cheaper) and it results in a nice, bright cookie with a rich flavor. The only problem seems to be that as the cookie settles, the green color quickly fades and begins to brown. This happens within a few days, even though the cookies are still fresh and perfectly fine to eat. I’ve done a quick competitive analysis and notice that other shop’s green tea cookies are also brown, leading me to believe this is something unavoidable. I believe the change in color is a result of the tea oxidizing, but I am wondering if there is a way to reduce or eliminate this effect. Does anyone have any experience with this? I appreciate any recommendations you can offer. Thank you!
8
2006
There are two factors contributing to the brown color: oxygen, and probably the bigger culprit with cookies and cakes, light.
My matcha stuff that’s combined with white couverture tends to fade, rather than turn brown, when exposed to light; however, I store those products sealed to avoid unnecessary instability.
But the Japanese bakery in my neighborhood found their matcha-an poundcakes turning brown within an hour of being exposed to sunlight. Their more stable products like macarons, shortbread cookies, and so on don’t have quite the same problem.
The high moisture content combined with light probably caused more oxidation.
I spoke with a Japanese tea company that makes a soap containing sencha and some matcha, and they found the only way to keep their product green was to resort to added coloring. Most Japanese companies making shelf stable matcha confections have some kind of added green coloring.
If you can seal the products you might have better color stability, but if that doesn’t work, you may need to adjust the moisture level.
I would also suggest playing with Vit C additives. Though the risk of vitamin additives may be a change in taste.
I wonder if dipping your cookies in white chocolate (or tinted chocolate) would help preserve their color?
Thinking about it more… maybe its a pH thing? Testing your cookies with varying amounts of acidic (citric acid) or basic (baking soda) levels would be interesting.
Maybe we just need to eat them all up straight away
So many great suggestions here, but I have to admit I really like Sam’s idea
Let’s eat them right away! Unfortunately in the cookie business that’s not always possible though.
It is really interesting to hear that many matcha products that remain a strong green color are probably using additives. I think some browning is inevitable, although I will try the suggestions about adjusting moisture levels and keeping them tightly sealed and out of light. I have already noticed that the ones we sell in individually sealed clear plastic stay better than the ones that are put on the shelves open in stores. This leads me to believe that the oxygen is a bigger culprit than the light.
Thank you for your help everyone. I will keep investigating.
Kelli, I’ve learned from everyone’s comment, although I like Sam’s idea best
I also suspect most people use colouring to keep the vivid green, I personally prefer natural colour even it’s a bit brownish.
Also, as I’m sure you know, this is one of the many reasons why so many Japanese baked goods come with their very own packet of dessicant!
These are great questions and answers. Q & A– it’s my favorite form of show & tell.
The acid idea might help a bit, as many bottled tea drinks contain ascorbic acid or similar, but I think the primary purpose of that is to control bacteria.
Also most baked things have some acid in them anyway, at least from baking powder, even if that’s meant to react with the baking soda. And green tea has a fair amount of vitamin C itself, though perhaps not enough to make a noticeable pH impact.
Oxidation essentially turns green tea into oolong or black tea, so it would certainly be beneficial for the flavor if it can be controlled. But I think most of the impact is at the surface, especially in moist cakes, where there’s a strong combination of light, heat, and oxygen.