Abstract: Food and Function
Sugar changes the chemical structure of tea and coffee
Is this effect of sugar in water on coffee solids to be trusted? I like some coffees black (pourover, drip) and some never without sugar (espresso drinks, Aeropress) and sometimes with evaporated milk or cream. I work at a coffee shop as well. Some have said that sugar counteracts bitterness in coffees (I assume due to caffeine). Does this supposed scientific backing have any credibility?
If you are asking whether the science can be trusted, I would say yes. The effect is already well known. You even understand it insomuch as you apparently don't drink more concentrated brews (espresso, aerpresso) without a "masking" agent.
All this study is doing is finding a more specific reason for the already acknowledged effect. People commonly believe that sugar or salt "masks" the bitterness from caffeine. This study is saying that sugar or salt are not just masking the bitterness, but actually changing the chemical properties of the caffeine in solution, thus changing the flavor.
I'm not really sure what you're asking here. Bitterness in coffee can come from many sources, the quality of bean, the roast, whether or not you've burned it, etc. Sugar can reduce this bitterness by triggering other taste buds on your tongue.
However, if you really want to cut the bitterness in coffee, just add the tiniest bit of salt (according to Alton Brown):
Salt and Coffee: Not only does salt cut the bitterness of coffee, but it also smooths out the “stale” taste of tank-stored water. I’ve taken to adding a quarter teaspoon of kosher salt to every 6 tablespoons of grounds. That isn’t really enough to taste, but it’ll do the trick. And by the way, research has proven that salt is actually better at neutralizing bitterness than sugar.
