Only 25% of what you perceive as taste comes from your taste buds. It was a little hard to believe, but you bought the idea. Good for you. Now you want to know How does aroma get from this hot chocolate I’m drinking to my brain in such a way that I can “taste” a smell? How many “smells” are there? And where do they come from?
Good questions. Let’s answer ’em.
Delicious Olfaction
Next time you pick up a piece of solid chocolate to taste it, give the bar a good ‘ol sniff. This is called “orthonasal olfaction” – smelling something with your nose. You won’t get much aromatic information from chocolate this way (as opposed to other foods like hot coffee or a grilled steak). That’s because the volatile flavor compounds in chocolate are not terribly active at room temperature. Remember your 6th grade science class? All molecules move when warmed. Volatile flavor compounds need a little heat to get going.
What IS a volatile flavor compound? Simply put, a VFC is a small molecule which has a high tendency to evaporate, especially when warmed. Volatiles are naturally produced by plants (flowers, fruits, vegetables, herbs), or animals. The flavors we are concerned with are almost ALL artificially produced, either by manufacture or by the normal chemical reactions that happen when we are cooking. Each VFC has a distinct aroma and flavorists have identified roughly 2000 of them!
What’s all this mean for chocolate? Bake that chocolate in a cake, put it in some cookies, just warm it up a little… and suddenly the smell of warm chocolate will set your mouth salivating. The volatile flavor compounds got active and now your nose can sense them.
For “eating chocolate,” like a Hershey’s bar, the warmth in your mouth and the physical action of your teeth are enough to spread those flavor molecules around. In other words, the majority of volatile flavor compounds in solid, room temperature chocolate will be released while you are chewing. Smelling what is in your mouth is called “retronasal olfaction” and it is VITAL to how we taste chocolate.
IMPORTANT NOTE
Do not mistake a handful of scientists IDENTIFYING a particular group of volatile flavor compounds with those same scientists UNDERSTANDING how the VFCs interact and combine to create flavor. Scientists have been able to uncover the basics, sure…. but the field is way too new and as of today, they’ve got NO definitive answers. For more on the ongoing research of the complicated interaction of VFCs and taste, take a look at the research paper at the bottom of this post under “Further Reading:” Associations of Volatile Compounds with Sensory Aroma and Flavor: The Complex Nature of Flavor
We learned in the Science of Taste post that the only question your taste buds can answer about chocolate is “I’m eating chocolate right now and it’s sweet, sour, bitter, salty, or rich.” There are additional sensors on your tongue which can tell you about the chocolate’s consistency, temperature, and whether it is spicy or not. The mighty buds can probably say something about the fat and milk content… but researchers are still arguing about that.
What about all the other flavors?
While you are chomping down on that slice of chocolate cheesecake, volatile flavor compounds are released and travel to the odor receptor sites in your nose via “retronasal olfaction.” Your brain decodes the smell message in the olfactory bulb and passes the information over to the gustatory cortex.
In other words, while you are chewing, you are also SMELLING what you are TASTING.
All of that information, put together into a big information chunk via the Gustatory Pathway in your brain – ALL OF IT – is what we call “flavor.”
BIG IDEA
volatile compounds in food are perceived by the odor receptor sites of the smell organ, ( in Your nasal CAVITY). They reach the receptors when drawn in through the nose (orthonasal detection) and via the throat after being released by chewing (retronasal detection).
Terroir and Single-Source Chocolate
Where does chocolate’s flavor come from?
Cacao absorbs the chemical components of the soil in which it’s grown, what chocolate experts call terroir.
Chocolate has many flavors, each of which are influenced by region, soil, climate and the chocolate maker themselves. Fine chocolate can taste of toast, citrus, berry, nut, smoke, coconut, earth…. It can be spicy, or floral or even medicinal. The flavors in a good bar of dark chocolate are not additives but comes from the cacao beans themselves. Like great coffee, artisan chocolate is complex, bringing many different flavors and sensations to your palate all at the same time.
This is why single-source (also known as single-origin) chocolate is so good and so expensive. Single-source chocolate is chocolate that’s made from one variety of cacao bean harvested in one region.
When different cacao beans from all over the world are blended, the effect of terroir is lost. Mass-produced chocolate uses inferior beans along with an entire concert of chemical additives to hide the poor quality. That doesn’t mean all blended chocolates are not good. In the right setting, a Hershey’s Kiss is delicious. However, for the truly great chocolatiers, the alchemy comes in finding that single perfect cacao region and figuring out just the right process to bring its flavors to life. That’s part of the challenge and the discovery.
Flavor profiles of beans from Madagascar have red berry notes, like strawberry or raspberry. Beans from Ghana tend to be fudgy and chocolatey where cacao beans are 50 percent fat. Beans from Indonesia taste smoky because they’re dried using a fire method. The highly prized rare cacao from Venezuela has a subtle and complex flavors that linger and change while you are eating them.
The amazing thing about chocolate is this: if two producers use the same beans from the same region, they’ll taste totally different because of the fermenting, drying and roasting methods and how much time the chocolate is in the conching machine. Again, quality chocolate is determined NOT ONLY by the heirloom bean used or the special location the tree was grown, but also the methods used by the chocolate maker that turn it into a chocolate bar.
Chocolate’s Many Flavors
The Chocolate Flavor Wheel
When we chew, we release volatile compounds into the air which are sensed through the retronasal pathway. These volatile flavor compounds are responsible for the majority of what we perceive as “taste.”
All of these different flavors have been classified on the “Chocolate Flavor Wheel,” a tool chocolatiers use to evaluate the quality of their products. Seems every manufacturer or fancy-pants chocolatier has their own version of this flavor map. Do a google search. You’ll be amazed.
The key take-away from any chocolate flavor map is this: there are 7 broad categories of flavor that a beginning chocolatier needs to be familiar with: caramel, nutty, spicy, floral, earthy, fruity, and vegetative. These are the types of flavors beginners will highlight based on the process and techniques used to make their chocolate.
Quick REVIEW: How We Taste Chocolate (the Super-Short Version)
All the things we eat are – fundamentally- chemicals. Each time we eat a piece of chocolate, some of the chemical compounds that make up that candy bar are registered by our taste buds as sweet, sour, tangy, bitter, or savory. At the same time, texture, spiciness, and temperature sensors in our mouth are sending signals about the chocolate that don’t have anything to do with taste and are more concerned with the physical attributes of the chocolate. And while THAT is happening, the aroma sensors in our nose are picking out many hundreds of flavor compounds that the taste buds can’t recognize and sending THAT information into the brain, too. Even the sound your mouth is making while it chews on that chocolate bar or hershey’s kiss or peanut butter cup is being relayed to our brain by the inner ear.
All this data combines together – not as separate facts but as one instant assessment. Somewhere in the Gustatory Cortex, up in the left hemisphere of our cerebral cortex, a judgement is rendered: “how does this chocolate I am eating taste?”
Highlighting Flavors
We’ve looked at balancing taste on the Science of Taste Post. When we are talking about flavor, though – it’s not so much about BALANCING as it is about HIGHLIGHTING.
Think about it. Sweet counteracts and balances Heat, sure. But what counteracts and balances “grass?” Or “caramel?” Or for that matter, “tea?” Nothing, that’s what. We aren’t trying to balance those flavor profiles, we are trying to either highlight them or diminish them through the process of preparation. We want to bring out the dark, smoky, fresh cherry flavors while diminishing the earthy flavors of mushroom or soil.
How do you do that? Very much the same way you highlight or diminish flavors while cooking.
Trial and error, baby.