How to make a perfect coffee: Lessons from world champion barista Aga Rojewska

Aga Rojewska, world champion barista, spills her secrets on making the perfect cup of coffee. Photo / Alex Burton

What happens when the best barista in the world takes over the office coffee machine? 2018 champ Aga Rojewska reveals the secret to the perfect espresso, and other caffeine hits. As told to Kim Knight.

"Espresso is a pretty difficult beverage to make and to drink. You either love it or hate it. It's very intense. It's like having a high alcohol experience. Some people love aged whiskies and some people just do whisky and Coke. It took me six years to be able to drink espresso with pleasure.

"You're looking for a balance of flavours. It's not bad if the coffee has acidity and bitterness, you just have to look for the quality of acidity and bitterness. I tell people the good cup of coffee is the one you'll drink again.

"In order to make espresso you need high pressure. It's very important to get freshly ground coffee - 75 per cent of aroma is lost after 15 minutes after grinding. A single shot is made out of 7g to 11g of coffee. It's a lot of coffee for a very short volume. A double shot is around 50-60ml, and the regular coffee we drink at home is like 200-300ml. The funny thing is that proportionally, espresso has less caffeine than Coke.

"On top of the espresso, you have a foamy layer that is called the crema and it should be somewhere in between gold and brown in colour. If there is no crema, it's not an espresso. If there is a hole, or the crema is not covering all the coffee, it means that either the people were too slow to serve it to you or they don't know how to make it. It should be served within half a minute of preparation.

"Just before drinking, you want to stir it. When you extract espresso, at the very beginning a lot of flavours and a lot of solubles are extracted. They are on the bottom of the cup, and every millilitre later [there are fewer]. So it might happen that the good flavours are on the bottom and the bad flavours are on the top.

"I do smell it after I stir it. The crema might be covering some of the aromas but, when they are released, they're not going to be there for long. They oxidise.

"If you have coffee from Central and South America, it's going to be pretty sweet. There is going to be some fruit, some caramel, some honey - all this stuff. African coffee will be more floral and Asian coffees will be more spicy.

"This coffee? I can try and guess. Probably this is a blend. If it's cheap it's probably going to be Brazilian. If it's a blend and not very expensive and mostly for milk coffees, it's going to be based in Brazil.

"When you take a sip, you don't have to think too hard - just drink it. Espresso is very dense, so it's just going to stay with you anyway. At the beginning it's going to be a little bit more acidic ... then you have a little bit of sweetness in the middle. It's not like a sugar sweetness. It could be more like roasted nuts, it could be a little bit like some fruits, it could be a little bit like dark chocolate.

"You take the sip, then you breathe a little bit, it oxidises. Then you're getting the after-taste. If the coffee is prepared in a good way, it's going to be something that wants to make another sip. if that doesn't happen, if you're having like old cigarettes or wood, or it's getting dry, it means that somebody doesn't know how to make coffee. Or it's a bad-quality coffee. If there is no after-taste, that means the coffee is under-extracted. If there is nothing happening, if you drink it and immediately forget about it, then something is wrong ... the quality of the bean itself, the quality of the roast, the quality of the water. It can be the quality of the barista. There are hundreds of possible reasons. My job as a barista is to get the best possible out of what I've got.

"Sometimes the temperature on the espresso machine might be a little bit high. I can see it on the crema, it's not very silky, not very glossy. It's getting these air bubbles and you can see it's disappearing pretty fast ... if the temperature is too high, the coffee will get too bitter. This happens in a lot of the machines.

Aga Rojewska can drink up to 30 cups of coffee per day. Photo / Alex Burton

"It's what you're used to. For example, my country [Poland] has a problem - the coffee is bad quality when you buy it. It's cheap and people believe you can buy good coffee in supermarkets. No. It's like you don't buy bread in a supermarket - you buy bread in a bread shop, right?

"With different temperatures, the flavour of coffee will change. Around 70 degrees you have the strongest aroma, you're going to have nice acidity and aftertaste. When it cools down to 50 or 60 degrees, you're going to have the highest sweetness and then the lower it goes, you get more of the fruitiness, the body and the textures.

"Every person has a different coffee habit. You would say a big guy, with big muscles, he would never order a latte - but it keeps happening all the time. Sometimes you don't expect the person to order a milk coffee or something very delicate. There are no rules.

"Most of the time we put sugar in because it's a habit. It's just like putting salt on a dish in a restaurant. First you try [to see] if it needs salt. The amount of milk in a cappucino is like already two spoons of sugar ... if you steam it to the right temperature it's going to be super-sweet without sugar.

"It depends on the day. Sometimes I can drink up to 20 or 30 coffees or it can be zero. I get a headache if the coffee is not prepared very well. I have very low blood pressure.

"I don't drink coffee in planes. They have bad-quality water there. Every single barista goes through the period in his or her life when you just travel with all this coffee equipment. Half of your suitcase is a grinder, a dripper, filter, scales - I don't even have the time in the morning. I prefer to spend half an hour in the morning to sleep than to make my own coffee. I learned that I can drink whatever coffee, if I need to. My friends are taking all this stuff on a plane and they ask for water and they grind coffee on this small table. I'm far from that.

"The first coffee I drank was [when]I needed to stay up late, because I needed to study. I was 17. It was instant coffee, like three in one - a bag of sugar, milk powder and coffee. I didn't even like it ... you just grow up into stuff. Maybe coffee is one of those things?

"Keep cups are a good trend. The coffee industry creates a huge amount of waste. Milk boxes, coffee grounds, cups, lids, stirrers, small packs of sugar. So if somebody can just bring their own cup. The thing is that people, most of the time, they don't clean it. This the pain in the arse. If someone cleans the cup and gives it to you to make a coffee, that's fine but not if you're having a keep cup after a cappuccino."

Poland's Aga Rojewska is the 2018 World Barista Champion and the first woman to take the title. She visited Auckland this month to run a masterclass and public workshop and to help launch a new support portal for baristas, baristasforbaristas.com