Categories
brewing coffee news

Ideal water composition for espresso extraction

The Coffee Science Education Centre (CSEC) in Australia tested the impact of a range of tap, artificially modified, and purified waters on the flavors of coffee in an espresso. The chemistry of the resulting brews and brew waters was analysed scientifically through gas chromatography with mass spectrometry, inductively coupled plasma optical emission spectrometry, a bank of photometers, and a series of pH/conductivity multi probes.

What a brilliant idea! I have long asserted certain differences in the flavors in a cup of coffee to the water used, but never really thought about it scientifically. Sometimes my favorite coffee tasted completely different when brewed at a friend’s home. Other times I simply couldn’t replicate the same great taste for a coffee I’d had at work in my home. I varied the recipe, tried to compensate for certain differences but never really solved the problem…

The study looked at how three elements of water affected flavours in extraction: hardness (the amount of calcium, magnesium, carbonate, and bicarbonate in water), pH levels, and total dissolved solids (TDS).

The biggest effect on flavour was achieved by modifying the hardness of the water

Dr Adam Carr of Seven Miles Coffee Roasters

They brewed an espresso on an industry standard machine from La Marzocco and then measured the concentration of chemicals in the coffee that are attributed to certain flavour characteristics, such as nutty/roasted (2-methylpyrazine), fruity (furaneol), vanilla/caramel (vanillin), and caffeine/bitterness (caffeine).

They found what I had sort of self-analysed by drinking coffee made with desalinated water, some mineral water and very hard (dH) water in my hometown in Bussum (dH around 9-10).

source: Seven Miles

Lessons learned:

  • Minimum hardness of 50 ppm for “best” flavors
  • Higher than 60 ppm has little effect on flavors
  • pH tends to concentrate flavors, much like salt enhances flavors in food
  • Higher pH tended to concentrate stronger flavours in coffee, though not to the same extent as hardness. However, higher pH levels also led to issues in the extraction process.
source: Reddit

Read the whole article to find out the recommended pH and what the effect on TDS was…

Source: https://www.beanscenemag.com.au/ideal-water-composition-espresso-extraction/

It just so happened that the water quality you want for coffee is what Sydney Water is pumping out of their stations!

Dr Adam Carr of Seven Miles Coffee Roasters
Categories
coffee news

So what kinds of coffee are there?

Just so it’s clear:

Great simple explanation of the different kinds of coffee drinks
Categories
brewing coffee news

The math of brewing a better espresso

Scientists have finally answered a burning question of mine: why should an espresso be brewed in 25 +/- 2 seconds and use approx 15-22gr of dry coffee to yield 50ml of (a double) espresso?

Who came up with this rule and why? Not that I have a specific problem with it but it seems so arbitrary. Also, once you start to make espresso’s a day long, you’ll notice that it’s really hard to dial in the equipment a certain way and maintain those rules for every cup. Sometimes it’ll be 21 seconds, sometimes 29. The grinder is pretty accurate. The beans are practically the same. So where does this high variation come from?

Well, it turns out that brewing your espresso differently yields the same great taste and flavors while achieving this with much greater consistency and reducing the cost per cup of espresso!

How did they do it? Well, they started by reducing the process to a proper model with solid mathematics behind it. Brewing an espresso is basically fluid dynamics of a bed of particles. The “puck” being coffee grinds of varying sizes and water is pushed through this bed at a certain pressure.

These mathematics are very well understood and accepted. So the scientists started with this model, created equations for everything and solved the equations using differential equations. That resulted in a few parameters and then they found the optimal solutions.

Sounds easy enough but believe me the math is pretty impressive, yet their logic is sound.

Turns out if you lower the pressure to 6 bars instead of 9, use 7-15gr of dry coffee, ground more coarse then tradition tells you to and aim for an extraction of 8-15 seconds, you will get a beautiful espresso that is much easier to reproduce!

Don’t believe it? Read the articles:

Categories
brewing coffee news training

Barista ethics, principles and practice

After working as a barista in various places since our return to the Netherlands in July 2019, I’ve learned that the coffee business is vastly better here than on Sint Maarten. The beans, the machines and the skills of the baristas working there are much better than there.

But what’s surprised me the most is that most places stopped after buying better quality beans or investing in a good machine.

Many places shamelessly use the same beans for espresso as well as “gewone koffie”, the historical Dutch name for normal coffee meaning filter coffee that our parents and grandparents used to make.

Some establishments use at least a different grinder when making “koffie”. But they opt using the same espresso machine because it’s there, so the “koffie” is most often approximated by a lungo.

A few use both a different bean as well as a separate grinder. A conscious decision. But I fail to understand why you don’t simply make “koffie” using a filter method?! After all, if it is about the money, and I think it is, then the math of making a liter of coffee from 57-63g of ground coffee is always better than turning 17-19g of the same coffee into 50ml of espresso or 90-100ml of “koffie”. Right?

And if you decide to use different beans for espresso and “koffie”, because of flavor I assume, then how come you don’t use different beans for cappuccino? After all, roughly 70% of coffee drinks sold in the Netherlands are “white coffees” aka milk-based coffees such as flat white, cappuccino, latte macchiato and large lattes.

I’m often disappointed by what I find in espresso bars during my Temper shifts. Large 3 group machines supplied by a caterer and left to more and more careless baristas who’s level of care and quality goes down by the month when management is not present, training is no longer provided and customers don’t know better.

Granted, many people working as barista are students either during the studies or directly after, earning money for leisure time, travel plans or settling down. They learn on the job while doing it and some of them are truly gifted and highly skilled by intuition. Nothing wrong with that. But as soon as they leave, and there’s always a better laying barista position coming next month – turnover is a bitch – knowledge is drained and whoever is left in charge has to pick up the slack. But pay is low, pressure is high and people don’t seem to care or know.

I’ve been searching for a better place to make excellent coffee now for 2 months and every place that I’ve talked to is stuck to bean contracts, doesn’t want to invest anything further and can’t train the people with SCA courses.

Well you can’t have it both ways! You want cheap high quality coffee fast, but you only pick two at any time. Not three. Skilled baristas cost more, care for the equipment, as well as customers. They know how to tweak the machine on a daily or even hourly basis to result in the best quality coffee.

Nothing makes a barista more happy than a great clean machine, new grinder or a kilo of fantastic beans to try out. Reward staff with perks, not salary. The effect is the same, if they truly love their jobs. Hire a legendary barista or roaster to give a workshop and spark their interest again, relight that fire (no, don’t go there!) and give the team a new boost of energy.

Categories
coffee news

Technical troubles on a tropical island

At work, our espresso machine broke down. The pump giving the 9 bars of pressure for the groups won’t start. But when manual flushing it works fine. Local coffee machine supplier Autobev says it’s the circuit boards. My guess is they were fried by a couple of successive power outages and a generator that did not kick in properly not timely.

On an island where everything is shipped in or flown in for emergencies, getting spare parts or qualified technicians is a bit of challenge.

We have several choices:

  1. Get full service from local company and have them order parts and do repairs
  2. Order spare parts from US and fly them in to have local company do repairs
  3. Ship machine to US to have it serviced under warranty and then ship it back
  4. Buy a new machine locally
  5. Buy a new machine in US and ship it to the island

Options 1-3 take several weeks, three at best, and there is no espresso in the mean time.

Option 4 could be good but depends on local supplies. On an island that still consumes vast amounts of instant Folgers, Maxwell House and Nescafé Coffee the odds are against you.

Option 5 is good but also takes at least 2 weeks.

We’re still looking at alternatives but lessons learned are:

  • Put equipment with circuitry on surge suppressors
  • Get a backup espresso machine for emergencies while your machine gets repairs
  • Get the numbers of all your equipment’s customer service and hotlines ready for the grab
Categories
coffee roasting

Sourcing Great Coffee Beans for Sint Maarten

Getting good coffee on this island is a challenge. That’s funny because we live right in the middle of the some of the world’s best coffee countries. So you’d expect a larger selection. Sadly, the opposite is true.

While every coffee selling business here seems to focus on making coffee from cups (Nespresso, Lavazza, Illy) and the local population mostly used to and stuck with cheap, large scale, commercially produced filter coffee such as Santa Domingo ground coffee, very few places have whole coffee beans to begin with.

When I started to make an inventory of the equipment needed to create a Specialty Coffee shop on St Maarten, I immediately noticed the lack of good grinders & espresso machines, long delivery times, uncertain product availability and total lack of good single-origin coffee beans. Malongo, a large French roaster with a presence on the French side of this island (Saint Martin) was the exception. Sadly, their stock was low, the beans old (almost a year after packaging date, no roast date mentioned anywhere!) and the selection limited to four countries: Brasil, Colombia, Rwanda, Ethiopia. And they had just survived hurricane Irma as well but I have no idea how good or bad their stock survived that storm.

So I am doing what everybody here does: if you can’t get it here and people won’t get it for you, you find and buy it yourself in the US, send it to Miami, FL, and have it shipped here by one of the several shipping companies that visit the island at least twice week. Here’s the list of roasters that I’ve contacted and who’ve replied to me they’d be interested in selling us beans at wholesale:

I’m very excited to make a choice from these wonderful companies, their coffee descriptions online give me a lot of confidence that they are indeed “Third Wave Roasters” and take quality seriously. I still have an order coming in from Malongo that will last a while, but their orders take 2 months to fulfill and that’s simply too long. I contacted Smit & Dorlas in Curaçao but they don’t have single origin coffees, only blends – but can ship these in 2 weeks -, and blends are not what I want to serve in the Double Dutch Cafe for black coffees, if at all possible.

I will blog about the progress that I’m making in getting serious coffee to St Maarten and having people take coffee more seriously on this island. 🙂