Beware The Hot Water Tap


Editorial Policy

Published on

Last updated on

[W]hile an espresso machine is made to pump, pressurize, and pour water to make drinks, there’s one water source on the machine that you should never, ever use for drink preparation: the hot-water tap. The small nozzle among the group heads and steam wands is a great tool to rinse pitchers, spoons, and demi-cups. The water from the hot-water tap is not fit for quality drinks.

The nozzle uses water from the main boiler of the machine. This is not where the groupheads get their water; they have their own, specialized boilers. The main boiler’s job is to produce steam to heat the grouphead boilers and power the steam wands. The water in the tank, while perfectly clean and healthy, cycles through the boiler very slowly and is re-boiled over and over under intense pressure.

Chemistry and thermodynamics are doing a number on the water in the boiler. When water is boiled over and over again, some compounds you need for extraction make their way out of solution, building up on the boiler walls, changing the mineral content of the remaining water*. You don’t directly control the temperature and pressure of the main boiler, or what’s happening to the water inside. Whatever qualities the water had when it entered the machine, the water that comes out of the hot-water tap could be something else entirely.

It’s an unknown, and you don’t want to make an americano or brew a tea with an unknown. Invest in a hot-water tower. Your drinks and your customers will thank you.

*For a more in-depth look at how water works and why you might want to think long and hard before using that hot water tap, check out Christopher Hendon’s article explaining how water works.

Cory Eldridge is Fresh Cup‘s editor.

Share This Article

Cory Eldridge

Join 7,000+ coffee pros and get top stories, deals, and other industry goodies in your inbox each week.

Other Articles You May Like

What’s the Deal with Mushroom Coffee?

Many brands are launching new products pairing mushrooms and coffee. A look at science and history reveals what’s driving this pairing.
by Leah Bowman | September 20, 2023

What You Need to Know About Barista Certification Programs 

Barista certification programs promise to teach learners new skills and can help with career advancement. But do they fulfill that promise? 
by Valorie Clark | July 21, 2023

The Cup In Hand: How Shape and Design Affect Coffee Drinking

The shape, weight, and feel of a cup can have a significant impact on the way you experience the flavor of coffee.
by Mikey Rinaldo | March 22, 2023

The Challenges of Coffee Certifications Go Beyond The Retail Shelf

Coffee certifications can be a valuable tool for farmers and roasters—but can be cost-prohibitive and difficult to navigate. We explore the benefits and challenges of certification programs before a coffee ever reaches the shelf.
by Anne Mercer | February 24, 2023