Boston masterclass announcement! Plus: Water chemistry, again

Boston Masterclass

I’m pleased to announce my first in-person roasting masterclass in three years. The class will be held in Boston on April 8 from 8-11am during SCA Expo weekend.

The class will include:

• Cupping and discussion of a new Roast Defect KIt

• Tasting of a few exceptional coffees, impeccably roasted

• A focus on roasting consistency, including designing and mastering one’s between-batch protocol— the cornerstone of a successful roasting system.

• Discussions of numerous advanced topics you won’t find discussed anywhere else.

Those who have previously taken my online or in-person classes are eligible for a 50% discount. Please email me (scott@scottrao.com) for a discount code.

Please click HERE for details and tickets

A short note about water

I’m inspired to discuss water chemistry yet again after having some recent disappointing coffee experiences due to cafe owners not using appropriate water-treatment systems.

There is a lot of information online about water for coffee. It can be confusing — almost every cafe owner I have spoken to about water has been confused in one or more ways. I’d like to discuss some common mistakes and offer a simple roadmap to ensuring you are using the appropriate, high-quality water for coffee.

Cafe owners and coffee enthusiasts often:

• Focus solely on TDS when evaluating water for coffee.

• Take advice from water-system vendors

• Think Reverse Osmosis systems are always the answer.

• Don’t bother getting their water tested properly by a lab.

Let’s talk about each of those issues.

Focus on TDS

TDS does not determine whether water is good for making coffee. In my consulting work and my seminars, I have often asked roasters and café owners to tell me about their water chemistry. 90% of the time, they quoted an estimate of their TDS, but had no other useful information to share. Unfortunately, TDS by itself is not much of a guide to the quality of your water for coffee brewing. The one minor exception is when TDS is so low that hardness and alkalinity are also necessarily too low. For example, if the tap water at a cafe in lower Manhattan has TDS of 25, the hardness and alkalinity are too low.

As I have written about on Instagram, this website, my books, and most recently in Standart Magazine issue 25, alkalinity, not TDS, is the single most important data point when considering water for coffee. If alkalinity is too low, coffee may be too sour or sharp, and if alkalinity is too high, coffee may be flat, chalky, or lifeless. Depending on your coffee and taste preferences, an alkalinity range of 20-50 ppm is reasonable for most. Of course, there are important factors beyond alkalinity, but if one wants to simplify the discussion of water chemistry, I recommend focusing on alkalinity first.

Taking advice from water-systems vendors

I have nothing against people who sell water-treatment systems. They often know a lot about water chemistry and treatment options. However, regardless of how nice and well-meaning they are, their job is to sell — and upsell — equipment. It defies common sense to get your purchasing advice from vendors. For example, a former client was planning a cafe in Manhattan, where the TDS was the aforementioned 25 ppm, and a vendor had talked him into getting a $3000 RO system. I explained to the client that he would be better off adding minerals to his water than removing them. He was confused at first, but also relieved to only have to buy a $500 carbon-filter system.

Reverse Osmosis systems are not always the answer

RO systems are often the answer, sometimes counterproductive (see above) , and always expensive. If one needs an RO system, one may want one with a bypass system, depending on the tap-water chemistry. RO removes approximately 90% of the minerals dissolved in water. If the tap-water alkalinity is, say, 100ppm, before RO treatment, it will be approximately 10ppm after RO. In such a situation, a bypass or blend-back system can increase alkalinity and hardness to desired levels by blending the RO water with carbon-filtered tap water.

As usual, there is no one-size-fits-all solution.

Test, don’t guess

A *appropriate* lab test of your tap water will cost approximately $100 — $150 and is essential for knowing with confidence what the best water-treatment system is for your needs. I say “appropriate” because most lab tests do not measure all of the important analytes. Please ensure your test measures ALL of these things:

• TDS

• General Hardness (bonus points if the test measures Ca+ and Mg+ separately)

• Alkalinity

• pH

• Fluoride

• Chloride

• Ideally, along list of various metals

In my consulting work, I frequently recommend a $125 lab test that measures over 30 analytes precisely and leaves nothing to doubt. With the test results in hand, plus the Langelier Saturation Index formula, I help clients choose the appropriate water system with complete confidence the result will be great-tasting coffee without scale buildup in machinery.