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Sometimes you just want a caffeine hit to wake you up, but if you appreciate the finer points of a cup of coffee, it’s worth going right down to the chemistry of the water, milk, sugar – and salt.

As a chemistry teacher, I’m inevitably fascinated by chemistry in general, but especially by the chemistry we come across on a daily basis. Rather than only sharing this with my students, I started a website, Compound Interest, where I create illustrated explanations of chemical concepts for anyone who’s interested to gain a better insight into the chemistry that pervades our lives.

So what can chemistry do for you? Well, for starters, it can help you make a better cup of coffee.

ChemexAny coffee connoisseur will tell you that good coffee should never taste bitter. However, in the less-than-ideal coffee world that the majority of us inhabit, bad, bitter-tasting coffee is much more common than we’d like. Luckily, there are plenty of tips out there on how to improve this, including the odd-sounding suggestions that adding a pinch of salt to coffee can improve the flavour. Science can help us explain how these suggestions might work – and how to make the perfect cup of coffee.

What makes coffee taste bitter?

Surprisingly, we still don’t know exactly what it is that makes some coffee taste bitter. Although the caffeine that’s present has a mildly bitter taste, it isn’t the main bitter component. Compounds called chlorogenic acid lactones and phenylindanes are thought to contribute; the former are in high levels in light- to medium-roast coffee, whereas the latter are found in darker roasts, and have a harsher taste.

Does adding salt to coffee temper bitterness?

Adding a pinch of salt might seem an unusual way to counter bitterness, but the science checks out. Researchers back in 1997 put it to the test by mixing salt into solutions of a bitter-tasting chemical and getting subjects to judge the bitterness. The volunteers consistently rated the solutions containing salt as being less bitter, despite the fact that the concentration of the bitter chemical in both solutions was identical.

The coffee-water balance

Remedying bad coffee-making with salt is a solution of sorts, but it’s better to tackle the problem closer to the cause. Extraction is a precise chemical process that can be tweaked in order to improve the flavour of your coffee. One important aspect is the ratio of coffee to water during the brewing process. Around 60g of coffee to a litre of water is recommended; in slightly more useful terms, that works out as a single gram of coffee for every 16ml of water, or around 7g for a single espresso shot.

The coffee-water balance is important because too much coffee can lead to greater extraction of bitter compounds, as the water is in contact with the coffee for longer. On the other hand, too much water will lead to a dilute, weak-tasting coffee.

Brewing time and bitterness

Brewing time is another important factor. At a simple level, there are three stages of compounds extracted from coffee. Acidic, fruity-flavoured compounds are the first to be extracted, followed by more earthy, caramel-like compounds, and finally the bitter-tasting compounds. Short brew times lead to only the first group of compounds being extracted, whereas over-brewing can lead to an excess of the bitter, astringent flavours.

For the best coffee, we have to aim between these two extremes. Different coffees come with different recommendations. For an espresso coffee, the water should only be in contact with the coffee for 20-30 seconds; in a plunger pot, this increases to 2-4 minutes.

Temperature and bitterness

Water temperature also affects the bitterness. The ideal temperature is between 91-96˚C – higher than this, and you’re likely to burn the coffee, increasing the concentration of astringent compounds. Lower temperatures lead to poor overall extraction of compounds from the coffee. Conversely, the much lower temperature of cold-brew coffee does lead to lower dissolved levels of the compounds causing bitterness, though it comes with the trade-off of a much-elongated brewing time.

Type of coffee and grinding

Even the best extraction technique in the world can be thwarted by poor-quality coffee. There are two primary types, arabica and robusta, with arabica widely considered to have the finer flavour. Robusta coffee contains higher concentrations of phenols, pyrroles, and sulfur compounds, leading to a flavour unflatteringly described as harsh and rubbery.

The size of the particles in your coffee grounds can also help or hinder. Too large, and the compounds will be extracted ineffectively, leading to weak-tasting coffee. Too fine, and the compounds, including the bitter-tasting ones, will be extracted too quickly. Again, it’s the case of finding that perfect balance.

Milk, sugar and coffee

If the honing of your extraction method fails miserably, you can always remedy your bitter coffee in a more traditional manner. Milk simply masks the taste, but it also contains the sugar lactose which can impart a degree of sweetness. Sugar, on the other hand, causes caffeine molecules to clump together, which along with its taste-masking ability helps to reduce the perception of bitterness.

It’s clear that a good cup of coffee is harder to create than you might have expected. Still, there are bound to be times when the quality of the coffee isn’t of primary importance – I know that, as a teacher, starting the day at six in the morning, I’m more concerned with getting the caffeine hit than I am with the finer points of coffee flavour. Nonetheless, equipped with the knowledge of the science behind the extraction process, a better morning coffee is within your grasp.

Source:  theguardian.com

Coffee 123Some believe it is healthy and energizing, while others claim it is addictive and harmful. When you look at the evidence, the majority of studies on coffee and health actually show that it is good for you. For example, coffee has been linked to a reduced risk of type 2 diabetes, liver diseases, Alzheimer’s and more.

The reason for this may be the impressive amount of powerful antioxidants found in coffee. In fact, studies show that coffee provides more antioxidants in the diet than any food group.

Coffee is Loaded with Several Powerful Antioxidants

Our bodies are under constant attack by reactive molecules called “free radicals.” These molecules have unpaired electrons that can damage important cell structures like proteins and DNA. This is where antioxidants step in. They donate electrons to the free radicals, effectively disarming them. This is believed to be protective against aging and many diseases that are partly caused by oxidative stress, including cancer.

Additionally, antioxidants can have various other biological effects and are considered to be very important for overall health. Interestingly, coffee contains very large amounts of several powerful antioxidants. These include hydrocinnamic acids and polyphenols, to name a few.

Hydrocinnamic acids are very effective at neutralizing free radicals and preventing oxidative stress. Additionally, the polyphenols found in coffee may help prevent a number of diseases, such as heart disease, cancer and type 2 diabetes.

Bottom line: Coffee contains very large amounts of antioxidants, including polyphenols and hydrocinnamic acids. These antioxidants may improve health and help reduce the risk of several diseases.

Dietary Sources of Antioxidants

Most people consume about 1–2 grams of antioxidants per day. The majority comes from beverages like coffee and tea. Beverages are actually a much larger source of antioxidants in the Western diet than food. In fact, 79 percent of dietary antioxidants come from beverages, while only 21 percent come from food.

Bottom line: Most antioxidants in the Western diet come from beverages such as coffee and tea. Only 21 percent of dietary antioxidants come from food.

Source:  www.ecowatch.com

Space coffeeAstronauts are getting a fancy new espresso machine and they also don't have to sip coffee out of Capri Sun pouches any longer.

Astronauts aboard the International Space Station (ISS) get 15 or 16 sunrises per day, but, for a long time, they didn’t get to wake up and smell the coffee.

That’s because coffee is distributed and consumed like all other beverages in space—freeze-dried and served in a pouch that has much more in common with a Capri Sun than with a steaming ceramic mug.

But that situation is finally improving, and the only thing it took was hosting more Italians from orbit. The SpaceX Dragon rocket scheduled to launch on Tuesday will carry a new kind of espresso machine to the ISS, called, fittingly, the ISSpresso.

Manufactured by Lavazza and the Italian aerospace firm Argotec, the ISSpresso uses standard Lavazza espresso packets to make coffee, tea, and hot chocolate. It also uses water the same temperature as in a standard Lavazza—167 degrees Fahrenheit—and mimics a real Lavazza’s water pressure. But, writing about the machine last year, the Space.com journalist Elizabeth Howell noted that very little else about the mechanism is the same. We also have very little idea as to how some of the ISSpresso’s internal mechanisms work. An Argotec spokesman has said the machine is adapted to prevent water leakage and spillage, a real risk in the orbiting laboratory’s microgravity.

The first person to try the fruits of the new Lavazza will be Samantha Cristoforetti, an Italian flight engineer from the European Space Agency who’s been on the station since late last year. She wasn’t the first Italian to note the poor quality brew on the ISS, though: A week into his 2013 flight on the station, another Italian astronaut, Luca Parmitano, said the thing he missed most was good coffee.

And Cristoforetti won’t even have to suck down the espresso from a pouch, too. Instead, she’ll use one of NASA’s new space drinking mugs. Called the Capillary Beverage experiment, these can be held like a cup, and drunk out of like a cup too.

Lavazza and Argotec say that findings from their experimental ISSpresso will inform future Earthly coffee machines. And NASA says the success of its new-fangled mugs will lead toward improvements in not only drug delivery on Earth, but also the design of future spacecraft.

And espresso may be a particularly fitting choice. Espresso is the quintessential coffee of the industrial age: One of the first patents for an espresso machine was filed in 1884, in Turin, the modern-day home of Argotec and Lavazza. Espresso sped up a normally tedious process through the sheer power of machinery and steam. It’s fitting that it should now join the space age.

Source: www.theatlantic.com

A Film About Coffee"A Film About Coffee" is a love letter to, and meditation on, specialty coffee. It examines what it takes, and what it means, for coffee to be defined as "specialty." The film whisks audiences on a trip around the world, from farms in Honduras and Rwanda to coffee shops in Tokyo, Portland, Seattle, San Francisco and New York. Through the eyes and experiences of farmers and baristas, the film offers a unique overview of all the elements-the processes, preferences and preparations; traditions old and new-that come together to create the best cups. This is a film that bridges gaps both intellectual and geographical, evoking flavor and pleasure, and providing both as well.

If you are in the coffee industry or just wildly passionate about coffee then this documentary is for you. You won't be dissapointed.

Coffee Shot GlassesA true Italian espresso cup is made from thick porcelain with a narrow curved bottom. This is not just because it looks stylish, like something Sophia Loren might have drunk from in Rome in the 1970s. The shape helps the crema, the velvety top layer, to rise, giving the espresso a more satisfying texture.

In many modern coffee shops "espresso" is served in straight-sided cups with a wide base. Hopeless! This is just one of many grievous errors being perpetrated against Italian coffee, as I learnt at the Espresso Italiano barista championships, which for the first time were being held outside Italy, at the grand Royal Automobile Club on Pall Mall. Three hefty coffee machines – each weighing 80kg to 90kg – had been shipped from Italy for the occasion, because – obviously – there was no machine in London authentic enough.

The competition was hosted by the Istituto Nazionale Espresso Italiano (INEI), whose mission is to "protect" true Italian espresso against imposters. Espresso, explained Carlo Odello, its communications manager, has "mathematical parameters". The beans are a careful blend – never the single-estate roasts favoured by hipster cafés. The coffee must be ground to a certain fineness. It is "extracted in so many seconds" to yield a potion that is neither too acid nor too bitter but redolent of citrus and almond: Italy in a cup.

Most of the so-called espresso drunk around the world is nothing like as purist as this. Either it is drowned in milk or served as a double – which doesn't exist in Italy – or experimented upon by "tattooed bearded artisans", as one Italian at the event complained to me. The INEI offers certification to cafés that still make the "original" espresso. But how can you "protect" something as universal as espresso? It's like trying to recork a bottle of champagne.

I like "bearded artisan" coffee, myself. And yet the INEI is surely right that there is something lacking in the paper buckets sold by the chains. I've noticed that in Britain, ordering a single espresso and a glass of tap water often provokes raised eyebrows, even though it's a far more controlled way to ingest caffeine than a giant mug of latte.

Author:  Bee Wilson


Coffee Culture Book SmallCoffee Culture is the latest publication from MapStudio, the publishers who brought us the fantastic Farm Stall to Farm Stall – a book mapping all the interesting and some fairly unknown farm stalls, including what they have to offer, along the roads of our gorgeous country.

Coffee Culture, the book about coffee for those of us that can truly appreciate excellent quality coffee and want to learn more about where we can get our hands on these cups of coffee, is now available at leading book outlets. Apart from pointing out where to find great coffee, coffee philosophy and brewing styles of establishments are also discussed.

MapStudio compiled this gem of a book, because as they put it, “Coffee has become more than just a ‘cup of filter coffee’ it has become a culture, and finding a good cup of coffee, is that much more important to many of us”.

Some light is shed on the history of coffee, cultivation, brewing equipment and methods as well as cleaning and maintenance of equipment.

Well done to Peter Primich and the Mapstudio team on a great publication!