Sweet, sour, salty, umami, and….bitter. Probably the least favorite taste. We all knew this moment would come: the post that dealt with my graduate school research. I promise I won’t go super nerdy on you though…just a little!
As you all know (or not depending on whether you’re a regular here haha), I am working toward a master’s degree in food science at Penn State. I was actually so excited when I heard about my admission to Penn State that I cried…quite a bit actually. The good news is that I was in the presence of great friends, so no embarrassment!
In my research I investigate the bitter taste and how to mask it for medication and health food applications. I have come across a lot of ideas about taste and how it is perceived. Bitter is by far the most interesting of the five tastes primarily because it is the most complex. Jennifer McLagan, the James Beard award-winning cookbook author, thinks bitter is the most interesting because it’s the least investigated. Her new cookbook Bitter talks about this aversion to bitter and uses recipes to elevate bitter ingredients.
My major professor, Dr. John Coupland, gifted me Bitter recently with the expectation, he told me, that I would write a fantastic post about our least-desired friend. Needless to say, I found it incredibly hard to work all day without peaking at the cookbook.
Bitter is a taste that is classically thought to have evolved in order to avoid toxins in the environment. It makes sense then, that plants would evolve to take on a bitter flavor for longer survival. This means that there are plenty of sources of bitter out there. Bitter is desirable in a few foods like coffee, beer, and chocolate, but overall, it is avoided like the plague.
Bitter has a very complex path from your food to your brain. First, the food dissolves in the saliva. Once in the saliva, it gets carried to taste receptor cells (I’m not kidding, that’s really how they’re referred to in the scientific field). The taste receptor cells are located within the taste buds. The taste buds are shaped a lot like onions with a small opening at the top called the taste pore. There are four different types of taste buds, actually, and each plays a different role in tasting.
Bitter receptors on taste receptor cells have more than 20 different genes on several different chromosomes. In comparison, sweet and savory only have one for each. Basically that means that we can detect many more types of compounds in foods as bitter that are shaped very differently from each other. On the other hand, things we recognize as sweet all have very similar structures to each other. It’s too bad really…I wish more things tasted like candy! From the taste receptors, the bitter signal moves through the central nervous system to the brain which registers it as bitter.
As an interesting fun fact, other primates have additional genes that code for bitter receptors. Those extra genes have become more of a wild card in humans. This is likely due to the fact that we have evolved due to cooking that reduces some of the toxins in food sources.
When you’re younger, bitter is even more pronounced than when you’re older. Taste buds are renewed constantly, but less and less are produced as you grow older. A big reason for this is because younger people had less experience and needed more indication as to which sources of food were harmful. It also explains why those brussels sprouts were so much more repulsive when your parents made you sit at the dinner table until you finished them and why coffee becomes something you appreciate when you’re older. Parents: keep this in mind, and take it easy on your kids!
Bitter tends to be the misunderstood taste, but Jennifer McLagan thinks it should be embraced. Her cookbook investigates different bitter sensations and ways of highlighting them. Grapefruit is commonly thought of as a bitter fruit and was discussed in several places of Bitter. She talks a bit about how grapefruit selection for sweeter tastes has “killed off” the bitter grapefruits. Regardless of this diminishment of bitter, McLagan includes several recipes for grapefruits.
I chose a grapefruit curd, but my grapefruit was not particularly bitter. Next time, I would reduce the sugar to let the grapefruit flavor sing a little more. I also tried freezing it in a spurt of ice cream whimsy, and it made a great cross between a sorbet and an ice cream. I’ll be sure to freeze all my curds in the future.
Okay enough nerd talk. Onto the recipe!
Grapefruit Curd
Barely adapted from Jennifer McLagan’s Bitter
5 ounces unsalted butter
1 large grapefruit
½ cup sugar (adjust slightly for taste)
2 eggs
1. Cut the butter into pieces and let sit at room temperature.
2. Grate the zest from the grapefruit and squeeze about ⅓ cup of juice from it. Strain the juice before using it in the recipe.
3. Process the sugar and zest in a blender or food processor just until the sugar turns slightly yellow. Add the eggs, blend, and add the juice continuing to blend. I used an immersion blender because I don’t have a processor or a large blender, and it worked really well.
4. Pour the blended mixture into a saucepan and cook it over low heat. Stir and heat until it coats the back of a spoon with a thick layer. I used a thermometer and cooked until it reached 176⁰F.
5. Transfer your mix using a strainer following cooking if you don’t like the zest in your curd. I personally didn’t mind the zest considering I strained the pulp (and seeds) from the juice at the beginning. Transfer the curd to your blender or use an immersion blender following straining for the next step.
6. Once your mixture has dropped to about 120⁰F, begin to add the butter one piece at a time. Blend the mixture for two more minutes following the addition of all of the butter.
7. Once the curd cools down, you can refrigerate it for several days or FREEZE IT!
A big thanks to Dr. Coupland for McLagan’s Bitter and all of the direction as well as all of the learning to come. Thank you for this massive opportunity!
