Few things in the world smell as good as roasting coffee. Even for non-coffee drinkers (and I suppose there may be a couple out there) it can be a sensational fragrance, like baking bread or barbecuing a chicken.

In fact, the odour of coffee beans being roasted should be made into airfresheners for your home or car – or maybe there already are, I just haven’t come across them yet.

Anyway, coffee roasting is a fascinating subject in itself, so let’s explore the world of the roasted bean.

Who First Roasted Coffee Beans?

Legend has it that a goat-herder named Kaldi discovered coffee when he noticed his goats being frisky after chewing the cherries of a particular plant. Kaldi tried some and found the same effect.

He took some of the cherries to a nearby monastery where the monks used them to stay awake and pray all night.

At some point the monks got tired of chewing the cherries and decided to try different ways of cooking them to make a drink, and eventually found that roasting them over a fire seemed to work the best.

Thus coffee roasting was born.

The monks passed this idea on to passing Arab traders (probably for a price) who took some of the plants and seeds with them to their home in Yemen, where the coffee business really started.

Originally the beans, which are actually the seeds of the coffee plant, were roasted in thin, perforated pans over fires with the beans being constantly agitated to make sure they were roasted evenly.

Is It Cheaper To Roast Your Own Beans?

Apart from the enjoyment factor – playing around with a roaster at home, trying different roast profiles and learning about the whole process – there is also a cost factor to consider.

Green coffee beans can cost from 50% to 75% less than commercially roasted coffee. In the USA for example, a pound of roasted beans will cost from $12 to $24 depending on the quality and the origin.

Of course some specialty coffees can be more expensive, for example a single-origin Hawaiian Kona roast will be around $50 a pound.

The average price of green beans is around $3 to $8 a pound, with some of the best single origin beans around $20.

Unless you are doing your own pan-roasting you have to take into account the cost of buying a roasting machine, and most decent machines average around $400 to $500 but for a family of coffee drinkers that would pay for itself in a year.

Complicating the cost / benefit exercise is that typically green beans will lose around 10% to 20% of their weight from loss of moisture during the roasting process, so that has to be factored in.

Since math was never my strong point I will leave it up to you to do the calculations, but it is obvious that home roasting will still come out ahead in terms of saving money.

Why Are Coffee Beans Roasted First?

Coffee beans are actually complex little things, full of chemicals, acids and sugars. However it takes the application of heat to bring these out and to produce the flavours and aromas we enjoy.

Of course you can chew the green beans just like Kaldi and his goats, but that is like eating a hunk of raw meat instead of grilling it into a nice steak dripping with the cooked juices.

Can You Make Coffee Without Roasting The Beans?

You can use unroasted beans in various ways.

Firstly by grinding them into a fine powder, which you then steep in hot water for around 10 minutes.

Secondly you can soak the whole beans overnight, then the next day you put them in a pan with water, bring it slowly to the boil, and let it simmer for around 15 minutes.

The drink made from the unroasted bean is not really recognisable as coffee, in fact it is a pale orange colour with a greenish tinge, more like green tea in appearance and taste – apparently, since I have personally never tried it.

There are claims that green bean coffee is a weight loss supplement and a health drink. The beans actually contain chemicals such as chlorogenic acid which has known anti-inflammatory and anti-bacterial properties.

These chemicals can be extracted from the green beans giving health benefits.

How Much Caffeine Is Present In Unroasted Coffee?

The good news is that the juice extracted unroasted coffee has a number of health benefits. The even better news is that the level of caffeine in green beans is less than half that of roasted beans.

For example, one cup of regular, medium roast coffee will have around 100 milligrams of caffeine. A similar cup size of green bean extract will be around 20 mg of caffeine.

However if you want less caffeine and still drink something like a real cup of coffee it is better to stick to decaf.

A similar size cup of decaf coffee will have only 2 mg of caffeine, but since caffeine does not add flavour – only bitterness and an energy jolt – you can still enjoy it as a drink, but it just won’t keep you awake.

What Is The Best Way To Roast Coffee Beans?

There are several good reasons for roasting your own beans at home.

Firstly, you get to learn and appreciate the roasting craft. You will probably make mistakes along the way through trial and error until you become a competent home roaster.

Secondly, you have control over the process and once you get used to it you can roast the beans to the level you want, whether light, medium or dark, or somewhere in between.

Thirdly, and most important, you get to drink the freshest roast coffee possible rather than from a packet that has been sitting on a shelf for a few weeks.

Methods of roasting can vary, from the traditional pan roasting, to roasting in your oven, even using a microwave. However all these methods can produce uneven roasts and can be messy.

The best method is to invest in a home roasting machine. Many people use popcorn poppers to roast beans, but if you are serious you need a proper home roaster.

There are plenty on the market ranging in price from budget models at $30 up to $1000 for state-of -the -art machines.

A good average would be around $500 and for that you get a solid, reliable roaster that is easy to use and produces consistent results every time.

What Happens When You Over Roast A Coffee Bean?

People who prefer light or medium roast coffee never usually have problems with over roasting. However, getting a dark roast can be quite tricky, knowing exactly when to stop the roasting process.

During the roasting process the beans lose their natural moisture and the darker the roast the more they dry out and start to burn. The gases like CO2 expand in the bean and start to push the oils to the surface, which is why a darker roast is more oily than a light roast.

The longer the roast time the more these effects happen, and if a bean is roasted too long all the flavour compounds are gone, leaving it like a small lump of charcoal. Coffee made from these beans will be smoky and ash-like, with a burnt and bitter taste.

How Do You Increase Sweetness In Roasting Coffee?

It sounds counter-intuitive, in that the way to increase sweetness is to roast the bean for longer.

We know that a longer roast time produces a darker roast, which is usually more bitter. The secret to sweetness is in careful judgement of the roasting stages.

The natural sugars in the beans develop during roasting. A light roast will have what is called a “bright” taste, meaning a bit sour, sharp and acidic.

This changes as the roast progresses into the medium and then the dark stage. As the roast becomes darker the sugars start to caramelize, and the key is to know when to stop roasting before they start to burn.

A good comparison is frying onions. A raw onion is sharp and sour. As you fry onions they become translucent and have a sweeter taste. Fry too long, they start to blacken and become bitter again.

This is called the Maillard reaction, a chemical process that happens when heat is applied to food, changing the colour and taste of the food item.

A good home roaster will know how to get the most sweetness out of the beans, mostly through trial and error, which means a lot of burnt beans before they get it right.

Do Coffee Beans Pop When Roasted?

During the roasting process the moisture in the beans turns to steam and tries to escape. At the same time the air and gases such as CO2 in the beans expand and also try to force their way out of the beans.

The result is that the cell structure of the bean starts to break down, and makes an audible cracking noise. Probably not as loud as popcorn popping, but a similar process.

It actually sound more like a puffed wheat breakfast cereal that makes a popping sound when you add milk.

When this happens in coffee roasting it is called the “first crack” and it tells the person doing the roasting that the beans are reaching the development stage, when most of the natural flavours and colour will start to develop.

For a light roast, this is the time to stop roasting. A bit longer and it becomes a medium roast. After a few more minutes the popping starts again, when all the gas and moisture leaves the bean. This is called the “second crack”, and is usually the time to stop the roast before it becomes too dark.

Can You Use Coffee Beans Straight After Roasting?

Okay so you have roasted your coffee beans, let them cool down, and you can’t wait to try them – but should you wait?

There is a lot of expert opinion that says you really should wait before grinding beans that have just been roasted.

Apparently the beans continue to develop their flavour and aroma for several days after being roasted. Coffee made with beans that have just been roasted can have a metallic taste, due to the remnants of the CO2 gas. The beans take a day or so to fully degas.

Most professional roasters will say that you should wait 3 to 5 days after roasting before grinding the beans.

However it is important at this stage to keep the beans in an airtight container, because as the CO2 leaves it is replaced by oxygen which starts the process of oxidisation, reacting with the oils and chemicals, and making the beans go stale.

When you look in your local grocery store or supermarket you will often find fresh roasted coffee sold in bags with a small valve which allows the CO2 to escape but not let oxygen in.

A clever system but difficult to do at home, so just keep them in a sealed container for a few days before using them.

Can You Drink Freshly Roasted Coffee?

Although the experts tell you to wait a few days, you can still grind and drink freshly roasted coffee beans.

Yes, it won’t be the level of perfection that it might reach later, but it is still fine to drink, and will taste just like coffee. In fact to the average coffee drinker like me (and I am guessing, like you) there will not be much difference.

Real coffee connoisseurs talk about the metallic taste of the CO2, and the green vegetable taste of nitrogen in the beans but it no doubt takes a very well-educated palate to pick up these flavours.

The possible exception to this is espresso coffee. The high pressure extraction method of espresso can reinforce and highlight the unwanted flavours, so it is recommended that fresh roasted beans should wait up to 5 days before being ground for an espresso machine.

What Are Sugar Roasted Coffee Beans?

Most European countries are known for their liking of dark roast coffee. The classic of Italian, French and Vienna roasts are all on the dark side and are in fact roast styles that are used around the world, not just in Europe.

Spain however has its own unique style of roasting, called Torrefacto. This involves adding white sugar to the beans during the roasting process, quite a lot of sugar in fact, up to 20% of the total roast weight.

What this does is when the sugar caramelizes and burns it makes a thin black layer on the beans, like an outer covering, which stops the process of oxidation and makes the beans stay fresher for longer.

It seems that this practice started during the post-WW2 years when many products including coffee were scarce, and it was a way of bulking out the existing coffee beans and preserving them after roasting.

It does sound a very strange practice, but it is still widely popular in Spain. But apart from slowing down the oxidation process, it does very little for the drink, in fact the burnt sugar coating gives the coffee beans a very sharp, bitter, earthy taste, much more than they would normally have.

Of course the question is, why do the Spanish still do this, when coffee beans are so plentiful these days? Well. I suppose they have just gotten used to it over the decades, and it has become a national habit. If you ever visit Spain you should try it at least once – you probably won’t want a second cup.

Concluding Thoughts

Roasting coffee at home can be a pleasurable experience, and also save you money.

It is also an interesting hobby with a rich history, and there are many things to learn about it while you roast your beans.

It brings a new dimension to life, and can make the whole experience of drinking a cup of coffee into almost an art form, with so much to try and so many different possibilities.

May we never stop learning – or stop drinking our favourite coffee!


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