Chances are you've had your coffee hot, cold and everything in between - especially if you're a parent like me who had every intention of drinking a hot coffee. Still, for some reason or another, your attention is demanded elsewhere and now you're left drinking a cold coffee. Or perhaps you've intentionally cooled your hot brewed coffee down with a few cheeky ice cubes- don't worry, we've all done it!

Whatever the reason, you've probably noticed that when you cool down your hot coffee, it doesn't taste quite as good as your favourite cold brew coffee. Besides the temperature, could there be something deeper going on in your cup that affects the way your hot and cold brew coffee can taste?

But let's dig a little deeper...

Unlocking the differences: Understanding taste

Disclaimer: While I don't claim to be a professor or doctor, I was a registered nurse for many years. But let's keep things "light and breezy" - Jake Peralta. 

Now that's out of the way. Let's take a little bit of time to understand how we taste.

In our mouth, we have a tongue, on that tongue are "taste buds" receptors. These receptors function as one of the interfaces between the chemical make-up of foods and liquids we ingest and the central nervous system. We've known for years that as humans, we have taste receptors for sweet, umami, bitter, and salty. When the food or drink we ingest comes into contact with the taste receptor, the receptor will excite the nervous system, telling our brain what types of flavours we are tasting. 

The nuanced differences in the chemical composition of the food or drinks that come in contact with our taste buds will result in different receptors getting excited, which then results in the perceived difference in taste. This is important because the chemical make-up of hot brewed coffee is different to cold-brewed coffee.

How does temperature affect the flavour of your coffee?

Hot coffee and cold coffee are two very different beasts. While they both might have been made with the same bean, they will taste very different.  

If we just look at the brewing temperature, you can clearly see why.

Let me explain... 

One way I like to think of making coffee is like food prep and cooking. After all, coffee is a fresh product too, you know. Let's take fish, for example. Most people have had it hot (fish and chips) or cold (sushi). Have you noticed that they taste completely different? Let's take it one step further. Have you tried to cook it without a lot of oil to try to be healthy, only to find that it comes time to plate it, and you're left thinking, "Damn that's a lot of oil and fats"? This is because when you cook the fish, all of the oils, acids, fats, etc. are expelled out into the pan. Let's relate this back to coffee - The fish is the coffee, the frying pan is your brewing temperature, and the oils and fats are your extracts from the coffee. 

Now let's summarise what we have learnt so far.

• The flavours of your coffee are a combination of extracted oils, acids, residual sugars, and caffeine.
• The extracts excite the taste receptors.
• Varying amounts of the proportions of these extracts will change the perceived taste.
• The brewing temperature directly affects the amounts of oils and acids that can be extracted.
• Hot brewed coffee extracts more oils and acids. Which our taste buds perceive as more bitter.
• Cold-brewed coffee extracts fewer oils and acids. Which results in our taste buds perceiving a less bitter, and sweeter brew.

So if you're cooling down a hot cup of coffee, there is no way that you can change or put back any amount of oils, acids, or residual sugars that have already been extracted during the hot brewing process.

The flavour of coffee is a combination of extracted oils, acids, residual sugars, as well as caffeine. But the amount of what gets extracted is directly affected by your brewing temperature. When you brew coffee with hotter water, it acts as an accelerator to speed up the coffee extraction process and extracts more oils and fewer acids. This results in a more bitter cup of coffee. 

Coffee brewed with cold water is slower and has much longer extraction times. The slower and more gentle extraction has a profound effect on the final flavour of the coffee, as cold water extracts less fatty oils and acids than hot water, which results in a less bitter, and sweeter brew.

Due to these differences in the chemical makeup between hot brewed and cold-brewed coffee, it now makes sense as to why they taste very different. As a general rule, the more the acids and oils you extract from your coffee, the more bitter your cup will be. 

Make sense?... Hope so. 

Think of it like food prep and cooking. Take fish for example, if you have ever had sushi, you'd notice that sometimes the fish is raw and it has a different texture and taste than when you cook it. 

There are multiple ways to cook the same ingredients, but when you use one method, the ingredients don't taste the same. The same goes here.

Why does cold-brewed coffee taste weaker than hot brew? 

A loaded question, right? To answer it, we need to define "stronger." There are two ways "stronger" could be determined. (1) How bitter the coffee is, or (2) the caffeine content of the final cup coffee. In my experience (over ten years on the specialty coffee scene and competitions in Melbourne), when a customer uses the word stronger, they usually think bitterness and caffeine strength are the same. This couldn't be any more wrong.

A coffee's bitterness is directly related to heat (during the roasting or brewing process), which allows for the extraction of oils. Think of this like cooking, when you heat your favourite ingredients, the oils that naturally occur inside the ingredients (which give them flavour) will be released. The same thing happens when coffee beans or grounds are exposed to heat.  

The caffeine content, however, is directly related to the length of time. In other words, the longer the brew time, the longer the coffee spends in contact with the water, the more caffeine is extracted.

Because both cold drip and cold brew coffee rely on cold water and no pressure, fewer oils and acids are extracted, allowing for a lighter and more floral drink and minimises bitterness. The slower process means the caffeine content is higher, too.

What does this mean for you? Well, at first, you'll taste your cold drip or cold-brewed coffee and think, "This tastes more like a tea, I can taste the flavours without the bitterness – it must be weak." Then 15 minutes later, you've got the shaky hands, and you've just smashed out a whole day's work.

Are cold drip and cold-brewed coffees a healthier option?

As mentioned above, coffee brewed with cold water extracts fewer oils and acids. Since cold brew and cold drip coffee have significantly less acidity than hot coffee, it may cause less acid reflux in people who are sensitive to it and/or be easier on the stomach or digestive system or for some.

The main point to consider is that the lower acidity and oils mean it extracts less of the beans 'defects, making the overall taste smoother, so you'll be less likely to pile sugar, milk or creamers into your cup.

So, what is better? Cold-drip or Cold-brew coffee?

Well, the honest answer here is that it's totally up to you! Both cold style brewing techniques will provide you with a mellower, less acidic brew, which is not only sweeter, lighter and more refreshing but also better for your gastric health than the hot counterparts. It all comes down to how you like to drink it.

These two cold brew coffee styles yield similar results, but their processes differ significantly. One may suit your lifestyle and flavour preferences more than the other, and that's what we're looking to find out.

Cold-drips often long extraction times are longer which results in a bolder taste, so if you feel like adding a little milk, we'd suggest going cold drip. On the other hand, cold brew's brewing style allows the aromas to shine through, making an enjoyable and almost bitter-less black drink. In saying that, they both are solid choices for summertime coffee vibes.

COLD BREW - Less hands-on. But becuase its treated as a concentrate it can be less convenient. The result? A very versatile, full-bodied brew, super-smooth, less acidic and highly caffeinated coffee that is great over ice, that is akin to a coffee concentrate that you can serve either hot or cold.

 

Until next time,

Stay caffeinated!