With that on the table, let's talk coffee. Coffee anyone? One lump(or is it "pump" these days) or two?
I feel a mixture of awe and horror when I listen to my friends talk about coffee (especially the ones that are baristas at various coffee establishments). Get two in a room and I swear the next two hours will be spent comparing how one store makes such and such drink or sharing stories of customers and general work stress. Since I know close to nothing about coffee, I'm left nothing else to do besides listen. And frankly, I couldn't care less about whether this coffee has hints of fruit or was brewed with this or that bean. Coffee aficionados may want to slap me now. However, I do know a few things about coffee that I will share with you today.
Coffee "Bean"
Coffee "beans" are not beans in the true sense of a bean. They are the seeds of coffee cherries (the fruit of the coffee tree). Picture two coffee beans flat side face to face comprising the pit of a coffee cherry.
Coffee beans are light shades of green before roasting.
"Light or dark roast?" the barista asks me. "Dark," I reply. I take take my coffee black--the darker the better. The stronger tasting, darker coffee must have more caffeine, right? According to my barista friends, it is actually light roast that has more caffeine. However, the real answer is (and true to my tax law background), it depends. Both answers are correct depending on which unit of measurement is being used to compare relative caffeine content: volume or mass.
The process of roasting beans does several things to coffee beans. First, the longer you roast a bean, the less caffeine it has. Second, the longer you roast a bean, the more water is evaporated out. Dark roasts are roasted for a longer amount of time than light roasts. So, if you take a cup (a unit of volume) of light and dark roast, the light roast will have more caffeine. However, if you use a scale and measure out a pound (a unit of mass) of light and dark roast, the dark roast will have more caffeine because dark roast weighs less due to having less water weight.
Hot Brew vs. Cold Press
The difference between hot and cold is the temperature of the water you use to extract the taste and aromatics from the grounds. Most people tend to be familiar with using hot water to brew coffee. A coffee maker uses hot water and makes coffee within minutes. Cold pressed coffee is made by letting coffee grounds steep in cold water for 12 or more hours. I'm not going to talk about whether using hot or cold water is better, that's up to you. Both yield a different coffee product. However, there are three concepts you should know which explain what's going on when you brew and those are: solubility, volatility, and oxidation.
The difference between hot and cold is the temperature of the water you use to extract the taste and aromatics from the grounds. Most people tend to be familiar with using hot water to brew coffee. A coffee maker uses hot water and makes coffee within minutes. Cold pressed coffee is made by letting coffee grounds steep in cold water for 12 or more hours. I'm not going to talk about whether using hot or cold water is better, that's up to you. Both yield a different coffee product. However, there are three concepts you should know which explain what's going on when you brew and those are: solubility, volatility, and oxidation.
- Solubility--Solubility describes a substance's ability to dissolve into something else. Adding heat generally makes things more soluble. Just as sugar dissolves more readily in hot water than in cold, coffee solids dissolve faster and more readily into hot water than into cold. One outcome of adding heat is that heat causes cholorogenic acid to degrade into quinic acid which contributes to the bitterness of coffee. However, heat also allows other acids and chemicals to dissolve into water which contribute to the signature coffee aromas and flavors we expect in coffee. Cold pressed coffee tends to be less bitter and acidic.
- Volatility--Volatility describes a substance's ability to become a vapor. Adding heat makes things more volatile. The steam you see rising from your cup of coffee is mainly water becoming a vapor. However, do you smell anything? If you do, what you're smelling are the aromatics being lost to the air. This means that the longer coffee remains hot, the less flavor it will have. Ever had stuffed sinuses and you couldn't taste a thing? Taste and smell are closely linked. Cold pressed coffee will retain aromatics longer in water, however, less aromatics may be in the water to begin with (see solubility).
- Oxidation--Oxidation describes the exchange of electrons when two substances come together. It's actually a much more complicated process, but you can read about that on your own. In the case of coffee, the effects of oxidation can most easily be tasted. Ever noticed that day-old coffee or rewarmed coffee has a different taste? Yum? What you're tasting are the coffee oils going rancid. Heat speeds up the rate in which coffee oils go rancid. Conversely, cold pressed coffee will taste fresh longer, anywhere from a few days to a week longer (as long as you store it in a fridge).
Fine vs. Coarse Grounds
Along with the amount of heat, ground size is another variable that affects the taste of coffee. In theory, you want to use a ground size that matches the method of brewing you will use. The finer the ground, the more surface area is exposed. The opposite is true for coarse ground. You want to use fine grounds for shorter brewing times (ie. espresso, drip, filter) and coarse grounds for longer brewing times (ie. french press, percolator). If you over steep fine grounds, you'll get more bitter coffee (more surface area is being exposed to heat/water allowing more coffee solids to dissolve). If you under steep coarse grounds, you'll have a weak coffee.
Along with the amount of heat, ground size is another variable that affects the taste of coffee. In theory, you want to use a ground size that matches the method of brewing you will use. The finer the ground, the more surface area is exposed. The opposite is true for coarse ground. You want to use fine grounds for shorter brewing times (ie. espresso, drip, filter) and coarse grounds for longer brewing times (ie. french press, percolator). If you over steep fine grounds, you'll get more bitter coffee (more surface area is being exposed to heat/water allowing more coffee solids to dissolve). If you under steep coarse grounds, you'll have a weak coffee.
Hope you didn't need any caffeine to get through this post!
Jack
No comments:
Post a Comment