Interview with Head Roaster Ivo: "We are constantly experimenting"

The roaster can have a decisive influence on the result in the cup through the type of roasting. But what is our roasting philosophy? Our head roaster Ivo reveals this and more in an interview.

While you are comfortably drinking your coffee in the sunshine of our outdoor area in Ackerstraße, in the café in Hackesche Höfe or at home, there is usually a lot of activity behind the scenes in our roastery. Every day, our roasting team makes sure that your coffees have the best possible taste. But how is the coffee actually roasted at Röststätte? How much experimentation goes into the roasts? And what do we place particular emphasis on when roasting? Ivo tells us all this and more in an interview.

Ivo, what is actually the roasting philosophy of Röststätte?

We roast only Arabica coffees that are classified as speciality coffees. In short, we do not roast dark, never until the second crack. We only roast the first crack. Nevertheless, we distinguish between filter coffee and espresso roasts.

What is the difference in roasting?

The espresso has a slightly longer development time during roasting and also a higher final temperature. But it is still not a dark roast, but something like a medium roast. Our filter coffee is a light roast, i.e. a light roast. This allows us to present the best aroma for filter coffee, but also the best for espresso. There are also the so-called Omni Roasts.

Do Omni Roasts have a disadvantage?

Omni Roasts are easier, for one thing, because you can create two products with one roast curve. However, many coffees do not necessarily allow this. This often results in the filter coffees being over-roasted to some extent - and if not, then the espressos are under-roasted. That means they are extremely acidic. And acidity can be nice, but we distinguish between positive acidity, which is sweet and comes from the fruit. And between a sharp acidity, which has a negative influence on the taste. And these present themselves in under-roasted coffees.

How do you rate the trend towards "omni roasting"?

In order to keep up with the competition, even those have to adapt sooner or later - and differentiate between filter and espresso roasts. A colleague has now even gone one step further and developed a dark roast - rather untypical for the specialty coffee scene - especially for the gastronomy. Otherwise, the scene is more focused on the individual customer - and not on the gastronomy. But the specialty coffee world is also a very dynamic field that is constantly reinventing itself.

The Specialty Coffee world is very dynamic and is constantly reinventing itself.

Ivo Weller, Co-Funder and Head Roaster

Are you still experimenting with new roasting profiles?

We actually experiment all the time. It always depends on the coffee and the time. Of course, we have some roasting profiles that can be adapted for many coffees. But that doesn't mean it's the optimum. So we keep experimenting. Various factors play a role: Where does the coffee come from? How high has it grown? How much residual moisture is there? And how fresh is it?

It may be a recent harvest, but it has been sitting for six months. The green coffee will then behave differently from one that was harvested only a month ago. It also depends on how the coffee was stored - cold and dry or exposed to heat. And also the new, experimental preparation methods (such as carbonic maceration) are new challenges for us roasters.

And when a new coffee comes along, for example our Alto da Serra – how do you proceed in the roasting team?

Then we experiment first. That means we try out different roasting profiles - and then look at the cupping to see which one fits best. For experimenting, we use a sample roaster from Ikawa, which is a roaster for smaller quantities of up to 100 grams. Otherwise we would roast masses of coffee – that would be a waste. With our large roaster, the Loring S 35 Kestrel, we roast at least ten and a maximum of 30 kilograms per run.

The new, experimental processing methods (such as carbonic maceration) are also new challenges for us roasters.

Ivo Weller, Co-Funder und Head Roaster

When do you usually roast?

Always at full moon (laughs).

No, seriously now. So I mean how often a week do you actually roast? And how is a roasting day structured in terms of time?

In our eyes, coffee is a fresh product. The freshness is what makes it special, which is why we roast it every week or even several times a week. We usually roast on Wednesday and Thursday or on Thursday and Friday. A roasting day with us starts in the early to late morning, and then ends in the evening at 5 pm. But of course there are also weeks like this, when we roast for days on end.

And how many new coffees do we roast per year?

We roast 10-15 new coffees per year. Apart from our classics, Sinfonia, Novum and Capital - which are available all year round - we also have many microlots. Sometimes we only get very small quantities of these, between 30 and 300 kg. For example, we only had ten 69kg bags of Paraiso. From Alto da Serra we only have one bag with 60kg. That's why our coffees change regularly, new seasonals and rarities are always added to the assortment.

Would you actually recommend roasting the coffee yourself at home?

You can do anything - if you know how. In the past, people roasted coffee with a hand roaster over an open flame. Whether you brew your coffee or make an espresso, you need a recipe for everything. When you put a piece of meat in the pan, you also need to know exactly how hot the pan needs to be, how long it should stay in there so that it's medium.

It's questionable, though, if you get the same result when you roast at home. After all, we have years of experience in roasting and work day after day to improve - this is noticeable in the taste. And who wants to smoke their home?

How do you actually become a roasting professional?

Master roasters" used to be an apprenticed profession. But this no longer exists, and now anyone who wants to can roast. However, a good roaster needs a lot of experience and knowledge, which he acquires over years. You can take training courses - but that's not really for private individuals. I myself trained as a chief diploma coffee sommelier and am also a Q grader (editor's note: this is the elite of coffee connoisseurs; the Q grader program of the Coffee Quality Institute is the world's most renowned coffee sensory training).

What makes a good roaster?

Besides the experience and knowledge, I attach great importance to cleanliness in the workplace. A good roaster should keep his area clean. I think it's terrible the way it looks in some roasteries - like a construction site, where the coffee is all over the ground and has to be swept up. Those are things I can't stand, because it's still food.

Thanks for the interview!

written by

Christopher Braemer

Christopher is a trained journalist and works in marketing at Röststätte Berlin. For the blog he writes about coffee from all over the world, but also about business, politics or sustainability.

Photos: Laura Droße

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