Barrel-aged coffee – maturity from the barrel
Unlike most coffee producers, we have always stored green coffee on our farmers' plantations.
Unlike most coffee producers, we have always stored green coffee on our farmers' plantations (still unhusked in the parchment or in the dried cherries) for up to a year after harvesting before husking it and shipping it to Europe. The common practice is to ship immediately after harvest, and it is still commonly believed that the ‘new harvests’ and the freshest coffees are the best. But this is far from the truth.
The real reason for shipping coffee earlier and earlier is the high cost of harvesting and processing and the associated financial needs of the farmers. In fact, once they arrive in the consumer countries, these coffees have a short shelf life and lose a lot of their flavour in a short period of time.
The coffees were processed too quickly and too fresh, causing them to lose a lot of their sweetness and aroma. This is because stress is triggered in the coffee seedling, which reacts enzymatically and initiates a germination process. During this process, long-chain sugars are broken down and restructured into cellulose compounds. This process is irreversible and cannot be stopped or interrupted once it has begun.
Cellular stress is caused by changes in temperature, humidity and light conditions. This occurs particularly during sea transport in containers, which are sometimes exposed to temperature fluctuations of up to 70°C during transport from the country of origin to the countries of consumption. Consider the temperature differences between countries and the heating of containers in the sun in tropical latitudes.
We have had many discussions with roasters who were firmly convinced that only fresh coffees are good coffees. Scientific understanding is best demonstrated through tastings, where participants always discover a much better balance in well-stored coffees.
Unfortunately, ‘freshness’ is much easier to convey and explain than ‘maturity’. But ‘maturity’ is the secret of all quality products and the basis for a balanced flavour profile.
No one assumes that fresh wine, beer, whisky or cheese is the best – we all know from experience that proper storage can transform a food product that is not yet fully matured into a small miracle of balance, flavour and aroma. It is no coincidence that the prices of mature or aged foods rise significantly. Incidentally, this applies not only to green coffee, but also to a certain extent to roasted coffee, which never develops its optimal flavour profile on the day of roasting or the day after – here too, depending on the roast profile, several days to weeks must pass to achieve the ideal maturity.
We have been maturing coffee in our coffee warehouse for many years and still have carefully matured green coffees from 2011. These have now become real treasures!
In order to substantiate and communicate this topic effectively, we looked for coffee maturation processes that developed special flavour characteristics.
In order to substantiate and communicate this topic effectively, we looked for coffee maturation processes that developed special flavour characteristics.
One of the best-known processes is undoubtedly monsooning from India. Here, the coffee matures under high humidity – the salt content also plays an important role – over several weeks in Mangalore in large maturation sheds (known as ‘go-downs’). The acidity peaks are reduced and the coffees develop aromas of caramel, peat and wood. The coffee loses its characteristic blue-green colour and turns ivory.
Originally, these changes occurred during the sea transport of coffee from India to England. With the advent of steamships and the opening of the Suez Canal, transport times were shortened (especially in tropical latitudes with high humidity) and the coffee no longer had the colour and taste typical of the British.
In addition to monsooning, there are also irritations in Java and Indonesia. There, the coffee is drained into brown colours and referred to as ‘Old brown Java’. This is also a very typical ageing or maturation process in the coffee industry.
Even today, coffees are still stored there – unfortunately without any specific storage and maturation plans – for up to 70 years in some cases, and then offered as low-acid specialities. I first tasted this coffee in a coffee house in Dublin. It was a completely different world of flavours, which even then prompted me to take a closer look at the subject of maturation and pursue it further.
While researching ageing, I came across the notes of a ship's doctor who described coffees of ‘special quality and with excellent flavour profiles’ that came from being stored in old barrels on ships. The idea of testing barrel-aged coffees was born. The question now was what barrels to use and what processing technique would work best.
We stored our coffees in barrique barrels (made of Limousin oak) that had previously been used to store Lemberger wine. In order to be able to trace the exact influences here as well, we experimented with a triple- and a six-fold barrel.
In order to be able to record the flavour transfer more accurately, we examined the aroma transitions in Canephora and Arabica coffees. We also examined the transition rates in younger and older green coffees.
As expected, younger coffees absorb the aromas more quickly and intensely than aged green coffees. Equally important is the movement of the barrels, which allows for even aroma absorption in the green coffee.
The advantage of storing green coffee is that it is microbiologically safe, as the coffee is subsequently roasted. Furthermore, after storage and roasting, the coffee contains no alcohol, as this is completely broken down by the high temperatures during roasting.
After a few attempts, we were able to produce ripe cognac tones in a fully washed SLN 274 from India in 2011 and rum notes with a fruity character in a fully washed Catuaí from Mexico in 2013. The transitions enhance the character and build on the basic sweetness.
During roasting, the barrel-aged coffees also exhibit completely altered aroma profiles in all roasting phases, which blend delicately with the roasting aromas at the end of the roasting process.
The barrel-aged coffees are suitable for both coffee and espresso roasting. The intensity of the cognac or rum notes in espresso is impressive, and balanced flavour profiles also develop in cappuccino.
We are planning further experiments in this direction and will soon be regularly storing coffees in different barrels in order to gain further taste experiences and, at the same time, have a good hook for illustrating the topic of maturation and storage with a prominent example.
Even without barrels, quality coffees should always be stored at the ideal maturity level, depending on the roast profile and desired flavour profile.
#Barrel-agedcoffee #Coffeematuration #Coffeequality #Coffeeenjoyment #Coffeeculture #Greencoffee #Storage #Aromaticdiversity #Coffeetasting # Coffeeknowledge #Monsooning #Espressoart #Roasting #Barrique #Cognaccoffee #Coffeeexperiments #Coffeeproduction #Luxuryfood #Coffeelovers #Craftcoffee #Slowcoffee
Even today, coffees are still stored there – unfortunately without any specific storage and maturation plans – for up to 70 years in some cases, and then offered as low-acid specialities. I first tasted this coffee in a coffee house in Dublin. It was a completely different world of flavours, which even then prompted me to take a closer look at the subject of maturation and pursue it further.
While researching ageing, I came across the notes of a ship's doctor who described coffees of ‘special quality and with excellent flavour profiles’ that came from being stored in old barrels on ships. The idea of testing barrel-aged coffees was born. The question now was what barrels to use and what processing technique would work best.
We stored our coffees in barrique barrels (made of Limousin oak) that had previously been used to store Lemberger wine. In order to be able to trace the exact influences here as well, we experimented with a triple- and a six-fold barrel.
In order to be able to record the flavour transfer more accurately, we examined the aroma transitions in Canephora and Arabica coffees. We also examined the transition rates in younger and older green coffees.
As expected, younger coffees absorb the aromas more quickly and intensely than aged green coffees. Equally important is the movement of the barrels, which allows for even aroma absorption in the green coffee.
The advantage of storing green coffee is that it is microbiologically safe, as the coffee is subsequently roasted. Furthermore, after storage and roasting, the coffee contains no alcohol, as this is completely broken down by the high temperatures during roasting.
After a few attempts, we were able to produce ripe cognac tones in a fully washed SLN 274 from India in 2011 and rum notes with a fruity character in a fully washed Catuaí from Mexico in 2013. The transitions enhance the character and build on the basic sweetness.
During roasting, the barrel-aged coffees also exhibit completely altered aroma profiles in all roasting phases, which blend delicately with the roasting aromas at the end of the roasting process.
The barrel-aged coffees are suitable for both coffee and espresso roasting. The intensity of the cognac or rum notes in espresso is impressive, and balanced flavour profiles also develop in cappuccino.
We are planning further experiments in this direction and will soon be regularly storing coffees in different barrels in order to gain further taste experiences and, at the same time, have a good hook for illustrating the topic of maturation and storage with a prominent example.
Even without barrels, quality coffees should always be stored at the ideal maturity level, depending on the roast profile and desired flavour profile.
#Barrel-agedcoffee #Coffeematuration #Coffeequality #Coffeeenjoyment #Coffeeculture #Greencoffee #Storage #Aromaticdiversity #Coffeetasting # Coffeeknowledge #Monsooning #Espressoart #Roasting #Barrique #Cognaccoffee #Coffeeexperiments #Coffeeproduction #Luxuryfood #Coffeelovers #Craftcoffee #Slowcoffee
Author:
Dr. Steffen Schwarz
Dr Steffen Schwarz is an internationally recognised expert in the field of coffee, an entrepreneur and a lecturer.
As the founder of the Coffee Consulate in Mannheim, he has for many years been dedicated to the training and further education of professionals across the entire coffee value chain. His work combines scientific insights with practical experience and covers topics such as coffee quality, sensory analysis, sustainable cultivation, and the processing and preparation of coffee.
Drawing on his many years of expertise, he advises companies worldwide, develops training programmes for the coffee industry and is committed to the responsible and quality-oriented handling of coffee. As an author, Dr Steffen Schwarz conveys complex specialist knowledge in an accessible and practical way, offering his readers new perspectives on one of the world’s most fascinating luxury foods.