Wired for Coffee Lab: What’s Crema?

Espresso with a fine crema on top
A nice rich crema makes the espresso look especially enticing. But is it necessary? You may not care for the bitterness and that’s Ok!

If you’ve just started or been around a short time on the upscale coffee scene, you’re probably puzzling out all the fancy barista tricks and tips.

One of the big ones is probably crema on your espresso shots and how in the world do you do it right?

It does seem a bit of a mystery doesn’t it. Here’s a secret for you.

The knowledge isn’t quite as hidden as you might think.

What is Crema?

Crema is that brownish orange to dark tan foam that sits on top of your espresso shot. It comes out of the spout first because of the CO2 that’s in the coffee beans. The gas gets released when the coffee is ground. The CO2 then emulsifies the coffee oils and gives the foam its body and aromatic smell.

When the espresso starts to come out, the crema mixes together with the espresso. It will then float up to its position atop the espresso. This is what gives your shot the “Guinness effect.”

Click any link in the table below to skip to your most pressing question, or continue on with the story.

It used to be a quality indicator but isn’t so much anymore. A really great looking shot of espresso with a great head of crema can be pulled and end up tasting pretty sour. While on the flipside, you can pull a shot of espresso with no crema and it will taste great.

A lot depends on the whole coffee process, including how much CO2 is present.

Let me explain…

What Does it Add to the Coffee?

Well, esthetically, the whole crema/espresso set up is pretty for one thing. Another is, if done right, it adds a bit of bitterness to the coffee. If you like that extra bit of bite, then crema is going to be something you’ll look for and get.

Some aficionados claim crema degrades the espresso and gives it a washed out taste. That may have more to do with too much CO2 in the formation of the crema. That can block the extraction of coffee.

This pushes more of the gas and less coffee into the liquid, leaving you with a weak espresso and the sour taste mentioned above.

What Affects the Crema?

There are a few things that affect the crema formation:

  • How it’s processed.
  • How it’s roasted. What kind of darkness it’s roasted to.
  • Roasting date. How new or old are your beans?

 

Let’s talk a bit about the process.

What Are the Three Processing Methods Used on Coffee Beans?

When we talk about processing, what we mean is how the pit or bean of the coffee cherry is removed and then prepared for roasting.

There are several but these are the three main ways. The others are takeoffs from these depending on the environment.

The Dry or Natural Method Process

Once the coffee cherries are picked, they’re laid out to dry in the sun. This usually takes about 2 to 3 weeks and they’re raked periodically until they’re evenly dried and the cherry has fermented away.

This is the oldest method of processing and is used in areas where there is a lot of sun and little rain like Africa, Brazil and Yemen.

The result is a heavy bodied coffee that tends to be sweet, smooth and complex. Beans that have been naturally processed will keep more of their sugars and oils. This helps them produce the most crema.

Their taste is more chocolatey and with a fruity flavor.

The Wet Process

This process uses high pressure water and machinery to remove the fruit that surrounds the beans. First they’re soaked and then run through a machine called a depulper to remove some of the fruit.

There’s still pulp left on bean, so they get a soaking in water to ferment which removes the rest of the pulp.

The coffee beans are than either dried out in the sun or dried in machines. This part of the process takes about 7 to 8 days while the beans are raked seven times a day.

This is a newer process used in countries like Central and South America where there isn’t as much sustained sunshine and there’s higher humidity.

It takes more of the sugars and oils out than the dry process. The result is a coffee that has a cleaner taste that is less acidic while being brighter and fruitier. These beans create less crema as a result.

The Pulped Natural Process

A bit of a combo of the dry and wet process because fermentation isn’t used. This is a popular process in countries with low humidity that allows the bean to dry out quickly when laid outside.

Environmentally, it’s a better practice because it doesn’t use as much water and there’s less wastewater as well. But it does remove the most sugars and oils from the bean. You get the least amount of crema with this process.

The result is a coffee with the same sweetness, body and aromatics that you would find in a natural process coffee but with the milder acidity that you find in wet process coffees.

What’s Meant by the Washed or the Unwashed Process?

Natural/dry process beans are called unwashed. Water isn’t used in the processing of the beans. They’re sun dried and the cherry ferments and breaks down on its own.

Wet process beans are called washed because water is used in the fermentation and removal of the cherry.

How Soon After Roasting Can I Use the Beans and Still Get Good Crema?

Crema is usually best if the beans are used 4-5 days after roasting. When it’s first roasted, you’re going to get too much CO2. The result is there won’t be enough extraction of the coffee oils.

You end up with more CO2 in your shot and not enough coffee. It looks pretty because all of the CO2 is emulsifying the fats and sugars but you won’t have enough coffee flavor.

It won’t taste very good…

Remember, you want some CO2 for the emulsification but not so much that it displaces the coffee solids that create the coffee you really want.

Too much longer than 5 days and the reverse is true. Not enough CO2 is left for good crema creation if that’s what you’re looking for. Otherwise, it’s perfectly fine to use.

What About the Roasting Color?

Dark roasting will pull most of the sugars and oils out to the exterior of the bean. They then get on everything the beans touch. The bag, your grinder and everywhere else. There isn’t a lot left to create crema so the darker roasts may show less crema.

 What Are You Using to Make Your Coffee or Espress?

Many super automatic coffee/espresso makers pressurize the coffee and inject air into the process giving you a fake crema. It’s noticeable because the bubbles in the micro foam aren’t the tiny ones created by CO2.

Some makes of stand-alone espresso machines will use pressurized portafilters that aerate the coffee during extraction. You get the same thing: fake crema.

If you don’t care about the crema, then these aren’t going to cause a problem. But if crema is your goal, steer clear if you can’t make the necessary changes to the equipment.

What Kind of Beans do I Have to Buy to Get the Best Quality Crema?

The best beans tend to come through the dry or natural method process. They retain more oils and sugars in the bean that can be extracted. That said, the most popular selections for espresso combine washed and unwashed Arabica beans with unwashed Robusta.

So…

Is Crema Something That You Want in Your Coffee?

It really comes down to taste. If you think you’ve pulled a great shot that just happens to be without the crema and it tastes good, then perfect.

You made a great shot of espresso.

Don’t kill yourself trying to perfect the crema. Try it with and without so you can decide for yourself. Don’t let the “experts” or your corner barista (or, ahem, me) tell you otherwise.

Don’t let them fool you. It’s your
choice. Taste test for yourself
and decide. Yes? Or No?

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2 Responses

  1. […] So, think it’s time to jazz up your coffee routine? […]

  2. […] The CO2 in the bean is released immediately on grinding and the coffee oils start to evaporate. The CO2 is important for crema formation on your espresso drinks. Once it’s gone, not much crema. […]

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