Kaffevand i Danmark

This post will be in Danish since it specifically concerns water for coffee brewing in the danish context.

Hvis du bare vil have det hurtige svar på hvilket vand du bedst brygger kaffe på derhjemme så kommer det her:

Køb kildevand med (bi-)karbonat indhold under 50 ppm.  Hvis ikke det står angivet som (bi-) karbonat kan det stå som HCO₃- eller måske endda bare HCO-. Om der står 50 ppm eller 50 mg/l gør ingen forskel.

Den lidt længere historie kommer så her:

Omkring 98,5% af din kop kaffe er vand. Ligesom Carl Jacobsen vidste hvor vigtig kvaliteten af vandet var for hans øl, er det vigtigt at man som barista ved, hvor vigtigt vandet er, for at få det fulde udbytte af ens kaffebønner.

Generelt er hanevandet i Danmark rent i den forstand, at det kan drikkes direkte fra hanen og sammenlignet med andre steder i verden er der sjældent nogen bismag (med undtagelse af lidt klor nogle steder). Problemet er bare at kalkindholdet er meget højt og at kalk neutraliserer mange af de smags- og aromabærende organiske syrer i fine lys- og mellem ristede kaffer.   

For at få det optimale ud af dine bønner derhjemme, bør du derfor købe kildevand til at brygge på. Specielt hvis du brygger mellem- eller lysristede kaffer. I hanevandet er der mange steder i Danmark et karbonat-indhold på omkring 200 ppm (eller mg/l), mens der i kildevand typisk er fra ca. 100 ppm og ned. For smagen er det dog bedst at komme under 50 ppm. De kildevand som er under denne grænse vil typisk skrive det på deklarationen, mens du godt kan regne med, at hvis ikke der står noget, så er karbonat-indholdet mindst 100 ppm.

Hvad de forskellige vandtyper i grove træk betyder for smagen er skitseret i følgende tabel:

Vandtype	Indhold af karbonat-ioner (ofte anført på flasker som bikarbonat eller HCO3-)	Gode vaskede kaffer smager
Hanevand	200 ppm	Fladt og bittert
Typisk kildevand	100 ppm	Medium livligt og aromatisk
Meget rent kildevand	under 50 ppm	klart, friskt og aromatisk

Alternativt til at bruge kildevand kan man filtrere vandet. Hertil anvendes forskellige typer vandfiltre. Generelt set er alle vandfiltre baseret på en af tre teknologier (eller en kombination af disse) - Kulfiltrering, Ionbytning eller Omvendt Osomose. Jeg vil ikke gå ind i en nærmere beskrivelse af de enkelte typer, men blot holde mig til det der er direkte relevant for kaffens smag. Hvis du overvejer at investere i et filter så find ud af hvilken af disse typer filtre der er tale om og lad dig ikke stoppe ved sælgerens forklaring om "at der er tale om en helt anden og ny type filter!"

Kulfitrering har den primære effekt at tilbageholde store og mindre smags- og aromabærende molekyler, heriblandt klor. Nedenstående princip-skitse illustrerer dette:

Men som det kan ses af skitsen ændrer kulfiltret ikke på indholdet af kalk i vandet! Så det beskytter hverken maskiner eller smag mod kalk!

De mest udbredte vandfiltre til kaffemaskiner er baseret på ionbytning. De fjerner den del af kalken, som kan give problemer i maskinerne. Desværre fjerner disse filtre ikke den del af kalken, som neutraliserer syrerne.

Når kalk opløses i vand, opløses det i kalcium-ioner (Ca²⁺) og karbonat-ioner (CO₃^2- og HCO₃-). Ionbytterfiltre tager som regel kalcium-ioner (Ca²⁺) ud af vandet og bytter dem med natrium-ioner (Na+). Ionbyttere fjerner altså kun en del af kalken, men ikke karbonat-ionerne. Desværre er det karbonat-ionerne, som neutralisrer syrer i kaffen og dermed dræber livlighed og fine aromaer. Og resultatet er en langt mere flad og bitter kaffe. Nedenstående princip-skitse illustrerer hvordan almidelige ionbytter filtre virker:

 Der er udviklet enkelte ionbyttere som bytter Kalcium-ioner ud med H+ ioner.  Disse H+ ioner kan "neutralisere" karbonat-ionerne. Som illustreret i følgende princip-skitse:  

Da karbonat-ionerne er væk neutraliseres færre af de naturlige organiske syrer og syrlighed og aroma bliver derfor ikke ødelagt på samme måder som ved andre ionbyttere. Det farlige ved denne type ionbytter er at H+ ionerne gør vandet meget surt og det kan ødelægge kaffemaskiner. Specielt espressomaskiner hvor vandet er under tryk bliver hurtigt tærret op af ionbyttere som tilsætter H+ ioner til vandet! Desværre ved vi at disse filtre stadig sælges til espressomaskiner selvom den medfølgende manual eksplicit siger at de ikke må anvendes til espressomaskiner. Så læs manualen grundigt før du vælger dit espressomaskinefilter!

For professionelle baristaer eller mere ambitiøse hjemmebaristaer mener vi, at fremtiden ligger i filtersystemer, som fjerner karbonat-ioner uden at forsure vandet - som eksempelvis Omvendt Osmose baserede anlæg. Man skal dog passe på med hvilket system man bruger, da nogle af disse systemer potentielt kan være dårlige for ens maskine. Hvis vandet er for rent (har et meget lavt mineral indhold - ofte målt som Total Dissolved Solids (TDS)) kan korrosion forekomme specielt i espressomaskiner.

Hvordan omvendt osmose virker kan ses i følgende princip-skitse:

Da det danske vand er relativt rent kan man lave en blanding af omvendt osmose behandlet vand og rent hanevand for at få mineralindholdet lidt op. Hvis man får karbonathårdheden op på ca. 40-50 ppm, vil det beskytte maskinerne bedre mod korrosion. Eventuelt kan man sætte et kulfiter på overløbet så man får fjernet kloren i vandet.

Vil man være helt sikker på ikke at korrodere sin espressomaskine sætter man først et almindeligt ionbytter filter på sin vandtilførsel. Herefter sætter man et omvendt osmose filter med et overløb med kulfilter på.

Vi er igang med et større arbejde for at finde frem til et omvendt osmose baseret filtersystem som både optimerer smag og maskinbeskyttelse. Men vi skal have lavet flere eksperimenter færdige før vi kan præsentere arbejdet nærmere. Indtil videre kan jeg blot løfte sløret for nogle preliminære tests som måske kan være brugbare for dem som gerne vil videre med bedre vand for kaffen allerede nu:

Vi har lavet nogle test af blanding af rent hanevand med omvendt osmose behandlet vand. De har vist at vi finder den bedste smag for almindelig brygning (filter, stempel, aeropress m.m.) ved en blanding med 5-10% hanevand (fra København som har totalhårdhed på ca. 300 ppm og karbonathårdhed på ca. 200ppm, TDS ca. 500 ppm) med 95-90% omvendt osmose behandlet vand (med TDS på 30-35 ppm). TDS i dette optimale vand var: 70-100 ppm og total hårdhed på 30-50 ppm og karbonat hårhed på: 25-40 . Til espressobryging vil vi dog anbefale at man laver en blanding som kommer op på en karbonat hårdhed på ca. 40-50 ppm. Hvilket med vores vandtyper svarer til 10-15% hanevand og 90-85 % omvendt osmose behandlet vand.

The Coffee Collective celebrate 3 years!

Tuesday February 15th

The Coffee Collective roastery and coffee shop on Jægersborggade turns 3 years.


We celebrate with free espressos the entire day and from 17:00 a special coffee drink on the La Esmeralda Special and Mikkeller's Beer Hop Breakfast with TCC coffee on tab.


Come celebrate with us!

The opening day on Jægersborggade. Yes, it's been 3 years now.



Last year's birthday party. Kid party style.

Kieni 2011

Well back from our trip to Kenya it's due time to share a little more of our experiences.

First of all, yes we bought an amazing lot of coffee from the Kieni wet mill.

As we wrote in the last blog post we were really hoping that the quality of their coffee would match last years. For us as a roastery it's not very satisfying to be shopping around for coffees from different farms or coops every year. We know the farmers depend on a good income to be able to produce quality. In Kenya however we've had difficulties relying on one mill, though. Perhaps because the top quality there is so outrageously good that and cupping there is like the best Cup of Excellence. We have really been hoping to build a relationship with the farmers there and this year it's the first time we're buying from the same mill two years in a row.

Casper with Kieni Factory Chairman Charles Musai Ihatu on the left and Factory Manager Geofrey Wanjau in the middle


On this trip we cupped around 300 different lots of Kenyan coffee. Around 100 of them were AA lots. Of them probably 10-20 was something we'd consider buying. Not to say there weren't some great coffees in the rest, but just not what we're looking for.



The Kieni had it though. The taste profile was very similar to last year. Heaps of black currant and dark berries but also some lighter citrus and floral notes came through this year. It still has that huge velvety mouthfeel and deep lush acidity. But it seems even sweeter and just more intensely aromatic. It's gonna be so much fun to nail the roast profile and see what we can get out of this coffee.



Naturally it was very interesting for us to find out if Kieni does anything different than the other wet mills in the area. The mill is definitely very well run by Geofrey. He strike us as very serious about the production, keeping things organized and clean. The Kieni factory is not the most impressive or beautiful we've seen in Kenya, but it's situated really well. The area where the drying tables are placed is almost shaped like a bowl, with a small valley at the end. This means the lots of air is coming through the area. The air is also not too warm, allowing for a cooler bean temperature while drying, thus reducing the risk of mold and fermentation processes at that stage.

Drying Tables at Kieni


The factory also has two fermentation tanks. It's common in Kenya to ferment the coffee for 8-16 hours after depulping in the first tank and then do an intermediate washing before fermenting the coffee again for some hours. With two tanks the intermediate washing can be done more carefully and thoroughly. After the first fermentation around 90% of the mucilage is removed. The last 10% is mainly in the middle crack in the bean and is then broken down during the second fermentation part. After that the coffee is washed in the washing channels and then put in soaking tanks in clean water, where they can be left for usually 6-12 hours but as long as 48 hours.

The Wet Mill:
Recieving Station at the top, depulper in middle, the two rows of fermentation tanks under the bottom roof and finally the washing channels.


After the washing process the parchment coffee is pumped from the soaking tanks onto the first drying tables for skin drying. The first tables are slanting a lot to let the water run off and the coffee contains around 55% moisture. After skin drying the coffee is moved to the more flat drying tables, where it's dried to 10%. It's important that the drying doesn't happen too fast, and for that reason the coffee is covered to avoid direct sunlight. It's also turned over constantly to allow for even drying and the raised tables of course allow for air to pass underneath and up through the coffee. The drying at Kieni takes around 7 - 10 days.



After drying the coffee is rested for another 2 weeks in a warehouse to stabilise the humidity inside the individual bean and throughout the entire batch.

One 'lot' on Kieni is typically one week's total harvest. We cupped lots from other weeks as well and they were also extremely good. The best surprise came the day after we had visited the Kieni mill. We had just decided that we were definitely going to buy one particular lot from Kieni, which had really stood out. As we were trying to arrange calls to the farmers, their marketing agent and our colleagues in Denmark to sort it all out, the Chairman and Factory Manager plus one of the board members from Kieni arrived at the Central Kenya Coffee Mill, where we'd been cupping. They were delivering that weeks lot from the factory.



It was a great pleasure to make the agreement with them right there and then, but even better was that we were able to cup their coffee together with them and talk more about our relationship with them. They are extremely happy to make direct sales. First off it gives them more money in their hands. This is the most important thing. Secondly, they take great pride in knowing where their coffee goes to. We had brought them a couple of bags of our roast of the Kieni we bought last year, and they had been really happy to show the farmers that this is where their coffee was going. As the chairman, Charles, told me, a lot of the farmers don't realise that their coffee makes it further than the factory. So they were happy and proud to see the factory name on the bag. He encouraged us to bring more bags next year. Will do.



One last thing that really struck us when we visited some of the farmers around Mugaga, was the incredible biodiversity there. It looks nothing like you see at larger farms. The coffee trees are growing right in the middle of lots of other trees: Bananas, mango, tree tomato and many other fruits all in a big mixture.

This is what a "farm" looks like around Kieni:


We also visited a lot of other societies and wet mills around the Nyeri region. Some we have bought from previously and others are cupping great or interesting in another way. Unfortunately we can't buy it all. But everywhere we went people were extremely hospitable and eager to explain what they are doing. Everybody we talked with also spoke very highly about the direct trade system, and they confirmed that is more profitable for them than selling through the auction.

A big thank you to Kieni for showing us around and selling us an awesome lot of their delicious coffee. Thank you to Bridget Carrington from Dorman's for a good time in Nairobi. Also a big thank you to Philip Kamau from C.M.S. for explaining SO much about coffee growing and processing in Kenya to us. And especially thanks to Ernest Njuguna from C.K.C.M. for picking out some awesome coffees for us to cup. He's an amazing cupper and a guy we really respect.

Casper and Ernest


We are now waiting eagerly for the Kieni lot to go through an extra hand-sorting and then get vacuum packed. It will then be carefully packed and the shipped in a container to Copenhagen. Let's hope there's not too many pirates in the water... Meanwhile you can enjoy the full set of pictures on Flickr or drink some of last year's Kieni or Gatina.



As part of Direct Trade we visit the farmers we buy from each year. You can see pictures and descriptions from each trip in our Flickr Origin Trips Collection.