Water, Water, Everywhere


Water, Water, Everywhere

Posted on Monday, January 13, 2014 - 8:30pm By Michael Harwood

At its purest, water is simply dihydrogen monoxide, better known as H₂0. But water is rarely found in its purest form; an effective solvent, water picks up baggage on its journey to brewing your coffee. So what amount and type of baggage is appropriate for brewing? The answer is that there are many waters that can help you get your brew where you want it to be; it largely depends on what coffee you’re using and what result you’d like to attain.

This is a little abstract. So where do we go for a concrete start, and what exactly are we looking for? Thanks to the Specialty Coffee Association of America, a solid set of water standards exists, which you can see here.

Odor - Clean / Fresh, Odor free
Color - Clear color
Total Chlorine - O mg/L
TDS - Target: 150 mg/L; Acceptable Range: 75 - 250 mg/L
Calcium Hardness - Target: 4 grains or 68 mg/L; Acceptable Range: 1-5 grain or 17-85 mg/L
Total Alkalinity - Target: 40 mg/L; Acceptable Range: At or near 40 mg/L
pH - Target: 7.0; Acceptable Range: 6.5 to 7.5
Sodium - Target: 10 mg/L; Acceptable Range: At or near 10 mg/L

If your water falls within these ranges, it is probably doing a pretty good job brewing your coffee. If you’d like your water to take your coffee to the next level, you’ll want to explore a bit more. Let’s touch on what these standards are and how we might think of them.

Odor - Smell your water. Does it smell clean, fresh, and odor free? Some waters smell metallic, soapy, chemically, rotten egg-like, sewage-like, medicinal, musty, moldy, or earthy. If you smell them in your water, you may be able to perceive these odors in your brew.

Color - Look at your water in a clean glass. Is it clear, ruddy, or cloudy? Cloudy water might just be air bubbles in cold, wintry water (let it sit for a minute or so to see if it clears), or it could be dirty. Ruddy water indicates rust and negatively influences how your coffee extracts and tastes/smells.

Total Chlorine - Discerned through aroma (does it smell like a pool?) or by a test kit, chlorine, chloramines, and others are disinfectants used to treat municipal water. With distinctive chemical aromas, it is a good idea to filter out these disinfectants.

TDS - Use a TDS Meter to take a reading. Total Dissolved Solids reflect the amount and nature of solids dissolved in water. Low TDS waters tends to overextract coffee. High TDS waters often have high mineral contents and tend to underextract coffee.

Calcium Hardness - Use a test kit to take a reading. Calcium Hardness is the presence of positively-charged calcium ions in water. There is also Total Hardness, which is a measure of positively-charged calcium and magnesium ions, among others, in water. High Hardness waters tend to underextract coffee and reduce acidity. Low Hardness waters tend to overextract coffee, raise acidity, and slow pour-overs drawdowns. Although some mineral content is critical to extracting oils from the coffee grounds, minerals do build up on boiler surfaces over time, causing a functional problem known as “scale”. Harder water creates scale more quickly, so cafes often have multiple carbon filtered lines with a softener built-in on the line to the espresso machine.

Total Alkalinity - Use a test kit to take a reading. Total Alkalinity measures the concentration of negative ions, which indicates the water’s ability to neutralize acidity. Think of Alkalinity as a buffer of acidity. To help me understand this concept, I like to imagine a leaky ceiling dripping into a bucket. The bucket is alkalinity and keeps the floor from getting wet for a while. Once the dripping (added acidity) is too much and the bucket overflows, the floor gets wet, changing its dampness (pH). High Total Alkalinity tends to subdue a coffee’s acidity. Low Total Alkalinity tends to promote a coffee’s acidity.

pH - Use a test kit or strip to take a reading. pH measures the concentration of H+ and OH- in a solution. The pH scale goes from 0 (most acidic, like battery acid) to 14 (most basic, like lye). 7.0 is neutral. An acidic pH tends to produce a more overextracted, acidic coffee. A basic pH tends to produce an underextracted, less acidic coffee that may feel flat.

Sodium - Use a test kit to take a reading. Sodium levels change the way we perceive tastes, so high levels should be avoided. Water softeners may raise sodium levels slightly.

Once you have taken the appropriate readings, you can develop the ideal filtration (keeping in mind that your water might change in composition at least once a year). At home, it’s hard to beat the ease and convenience of a simple carbon filter like the oft-used Brita pitcher. If you live in an area where the water is quite hard, your best bet may be to source water from a nearby cafe, roastery, or grocer. In a commercial cafe setting, there are several options depending on your water needs. For harder water, a Reverse Osmosis system with blend capability or a water softener with a carbon filter may be in order. For cafes with soft to moderately hard water, a basic carbon or activated carbon filter may work well.

To help understand hardness/TDS in a different way, I have an analogy: Imagine a bellhop as you pull up to a hotel with your family and all of your bags. The distilled bellhop (Almost zero TDS/Hardness/Alkalinity) has no hands and can only take away one bag under their arm, thus underextracting your coffee. The Low TDS/Hardness/Alkalinity bellhop is underworked and overenthusiastic. This bellhop grabs all of your bags at once and even snags your baby under their arm. This leads to overextraction. A third, SCAA standard bellhop is attentive, but not desperate. They pick up just the right number of bags from your taxi to keep everything organized and well-extracted. Then there’s the stinky bellhop, who may have been drinking chlorine this morning. They may get your bags to the right room, but your extraction may smell funny afterwards. Finally, there’s the bellhop who is overworked and already has their hands full (High TDS/Hardness/Alkalinity). This bellhop tries to pick up your luggage anyway, but is only able to grab one or two pieces, leaving your brew underextracted.

If you are in the market for bottled water, do your best to avoid deionized, distilled, and harder spring/mineral waters, as these will not extract your coffee well. Although it is a little soft, Gerber Pure Water satisfies many of the SCAA Water Standards and has a high level of transparency. I am told that a certain former Ceremony Head Roaster and two-time United States Brewer Cup Champion favored Deer Park, which seems to have a wide range of possible attributes as it comes from multiple sources. Another Ceremony patron expressed a preference for Walgreens’ Nice brand. Some spring waters are too hard, so do a little online research on their latest water quality report before you hit the grocery.

Depending on where you live and the condition of your building’s pipes, you may even be able to get away with unfiltered tap for pour-over brewing. I’d almost always recommend carbon filtration, but in the water tasting and brewing experiment we did recently, the unfiltered tap water from our roastery held up quite well to the other filtered options. It smelled of chlorine by itself, but that odor barely registered in the brew. Unfortunately, I don’t feel quite as positively about the unfiltered tap water from my apartment in Washington D.C. Just like with real estate, water quality is all about location, location, location.

This past Friday, we invited the public in for a water-based cupping. The idea was to taste five different waters, then to brew two different coffees with each of the waters to observe their extraction and in-cup characteristics. Here’s what we found:

TYPE OF WATER Distilled Soft (RO with Minerals) Filtered Annapolis Tap Unfiltered Annapolis Tap Hard Spring
ODOR None None None Chlorine None
COLOR Clear Clear Clear Clear Clear
TOTAL CHLORINE 0 ppm 0 ppm 0 ppm 0.75 ppm 0 ppm
TDS *Approx. 0 ppm 30 ppm 150 ppm 160 ppm 300 ppm
CALCIUM HARDNESS 0 ppm 10 ppm 70 ppm 70 ppm 150 ppm
TOTAL ALKALINITY 10 ppm 70 ppm 50 ppm 50 ppm 160 ppm
pH 7.5 9.5 8 8 8
Sodium 0 ppm 18 ppm 3.48 ppm 3.48 ppm 20 ppm
Distilled Soft (RO with Minerals) Filtered Annapolis Tap Unfiltered Annapolis Tap Hard Spring
Brazil Cerrado medium acid, thin body, under extracted low acid, medium body, soft mouthfeel sweet, rounder, best flavor, full body sweet, rounder, good flavor, fullest body low acid, low sweetness, muddled, heavy
Kenya Kabare high acidity, some sweetness, thin body, under extracted low acid, thin body, soft mouthfeel, slightly bitter, good flavor juicy, sweet, best flavor & balance, full body juicy, sweet, fullest mouthfeel, good flavor low acid, low sweetness, muddled, heavy

As you can see, we found the best results with the 3M carbon filtered tap water from our Training Lab. Coming in a close second was the unfiltered tap water straight from our roastery sink. Not bad, Annapolis! The RO water with trace added minerals did have a nice, soft mouthfeel, but overall, the experience wasn’t complete. Most articles we’ve read say to never use distilled water for brewing, so we were surprised that it didn’t make for the worst brew. That said, I wouldn’t recommend distilled water unless you were in a bind. Our least favorite was the harder Spring Water, which didn’t develop the coffees’ flavors and was very muddled.

The differences in how the waters affected the two coffees was fascinating. One of the main varying characteristics was acidity. We found acid-subduing waters (higher hardness, pH, alkalinity, and TDS) seem to do better with coffees that are lower acid to start with. For example, we found that the deeper Brazil Cerrado was more enjoyable with soft RO water than the brighter Kenya Kabare was. We suppose this is because the Brazil had less acidity to lose than the Kenya did. Since we’re looking for acidity in our Kenya, we were disappointed that the RO water did not bring it out. However, if you are looking to subdue acidity, you may want to look for these higher attributes in the water you use.

The bottom line is that having water within the SCAA acceptable range is important to bring the best out of your coffees. Within that range and even on its fringes, don’t be afraid to experiment to see what you can bring out in your coffee. If you find a great water for brewing, please let us know!

One of the big takeaways from our experiments is that even with different waters, if you start out with well-sourced, well-roasted coffees that are freshly roasted, ground, and brewed, you will end up with a brew that is better than most coffee out there. This is only to say, don’t get so wrapped up in water chemistry that you forget the most important variable of all, the coffee itself.

Until next time, happy brewing!