Distilled water for espresso?

Short answer

Pro and semi-pro coffee makers (example: Simonelli Oscar) generally need minerals to measure the water level and activate the pump if the level drops. With distilled water, the current does not flow, the pump may work strangely and break the machine. Suggestion: use spring (or tap) water and pass it through a pitcher type softener filter (Brita) for those who have a tank or a 3M cartridge filter for “direct connect”.

And not for types of preparation such as filtration, immersion (piston, clever).

Long answer

First of all, the idea of ​​using distilled water to prevent calcium buildup in the machine is noble and serves its purpose. If in residential grade machines, such as Seaco, this does not really matter, it is quite different for pro and semi-pro coffee makers.

We must remember that coffee is 99.9% water. And that the aromas, textures and perfumes of coffee are hidden in the aromatic oils contained in the roasted bean. Preparing coffee is therefore simply a process of impregnating these flavors into the water. The same goes for tea, rice pudding, oatmeal. Why rice pudding and oatmeal? Well it's because I made some yesterday, and in the recipe, they make us add salt. This salt (a mineral) allows aromas to be transferred to liquids. Same thing with coffee, the heat and minerals in the water are essential to extracting the flavors from the coffee.

So, in order to have good coffee, it is essential to have mineralized water. If distilled water is used, the coffee will be weak and flavorless. A bit like my oatmeal without the pinch of salt.

For filtration or immersion type preparations (piston, clever), the result will be striking between distilled and normal water with minerals. On the other hand, in the case of espresso, we are faced with a different method of transferring aromas which does not necessarily require minerals. For espresso, hot water (195-200F) passing through a tightly packed, finely ground coffee wafer, at a pressure of 10-15 bar, should last 25-30 seconds. This extraction speed places water and ground coffee in contact in a very short period of time, making the usefulness of minerals in flavor transfer secondary. And on the other hand, the minerals will contribute to the accumulation of solid residues in the pipes and the kettle of our machines. This accumulation has the extreme risk of damaging the machine. This is why it is important to decalcify your machine regularly. If you don't know how to do it, consult the manual for your machine or take it to a service point.

So, for residential machines, using distilled water in your machine can save you a lot of worries.

But if I'm writing this today, it's following the sale this afternoon of a Nuova Simonelli Oscar. By the way, did you know that we were depositaries for this brand? What followed was a discussion with my client about the use of distilled water with this type of coffee maker. I explain to him why it's not necessary and bang! I just thought I forgot to tell those who bought some in the last 6 months...

Because for owners of professional and semi-professional coffee makers, distilled water should be banned. And Oscar is a semi-pro. For what ? Despite the maintenance benefits of using distilled water, the internal workings of the machine use water as a conductor to determine the level.

So, in the case of the Oscar, this type of machine uses a technology called a heat exchanger to regulate the water temperature and uses a physical probe (autofill probe) to regulate the water level in the kettle. This probe sends a low voltage electric current which, when it touches the water, uses the water as a conductor, passes through it to the "ground" of the kettle to determine the water level by sending a signal that stops the operation of the pump. If the water level drops, the electrical contact between the probe and the kettle ground is no longer made, a signal activates the pump. So this system ensures that the heating element is submerged in water and prevents it from heating up in the air (which breaks the element). It is also this system which prevents the pump from overworking by sending it the signal “Stop, the kettle is full”. Okay, I'm starting to ramble, I'm sure you understand.

So, using distilled or reverse osmosis treated water, the water will be too pure for the circuit to use water as a conductor. Electricity needs minerals to circulate. Depending on the machine, this can damage it over time since the water level information is non-existent.

Ideally, you should use water with a very low calcium and magnesium content (so that these minerals do not end up blocking the coffee maker) but which contains the other minerals which will allow its conductivity.

Using spring or tap water, which you can pass through a softener, which will reduce the hardness of the water by reducing (or completely eliminating depending on the system) calcium and magnesium.
I suggest using a pitcher type softener (Brita), changing the cartridge regularly, and feeding your machine's tank with this water.

You want to make espresso like a pro, well, welcome to the club!

Dany

Here is a top 5 of our coffees that are delicious as espresso:

1. The Bad Boy Espresso
2. The Inspiri Organic
3. The Bad Girl Espresso
4. Organic Italian Espresso
5. The Special Cream

You can also browse the following texts published on our blog:

• The 4 M’s of espresso
• What is espresso?