Royal Coffee Blind Tasting of Waters

#1: Post by **NoStream** » September 11th, 2018, 4:52 pm

https://royalcoffee.com/treading-water- ... sory-data/

Best article on water I've read in a bit. They preferred low carbonate, and slightly preferred calcium to magnesium hardness. Most surprisingly, they liked distilled water a lot!

September 11th, 2018, 5:08 pm

I wonder how they brewed the distilled water. I've done dozens of public blind tastings with steeped (French Press) brews. The distilled water brews are always the outlier: everyone instantly hates them, since they taste, thin, soury, and harsh. The other waters (scale safe 50 ppm up to 225 ppm) get mixed reviews.

September 11th, 2018, 6:07 pm

My experience with distilled was that it was a bit lacking in sweetness and flat but not awful. On the other hand, super high carbonate water tastes pretty awful to me (chalky / bland / no acidity).

Maybe part of my preference for custom water (1 part magnesium to 2-3 parts carbonate on a molar basis) has been placebo and I could have gotten away with charcoal-filtered tap.

#4: Post by **RyanJE** » September 11th, 2018, 11:09 pm

another_jim wrote:I wonder how they brewed the distilled water. I've done dozens of public blind tastings with steeped (French Press) brews. The distilled water brews are always the outlier: everyone instantly hates them, since they taste, thin, soury, and harsh. The other waters (scale safe 50 ppm up to 225 ppm) get mixed reviews.

It looks as though this was all done via actual cupping.. which also makes me wonder how / if brewing via espresso would change things.

Maybe we can arrange someone on HB to do a water shoot out of some sort! I wish I could, but have a really novice palette..

September 12th, 2018, 2:09 pm

Odder and odder: cupping and French press are identical in terms of the brew produced.

#6: Post by **soadasopa** » September 24th, 2018, 2:39 pm

another_jim wrote:I wonder how they brewed the distilled water. I've done dozens of public blind tastings with steeped (French Press) brews. The distilled water brews are always the outlier: everyone instantly hates them, since they taste, thin, soury, and harsh. The other waters (scale safe 50 ppm up to 225 ppm) get mixed reviews.

I have found this to be true in my experience as well.. however I remember one experience cupping with a roaster who used 0 ppm water (not sure if it was softened, or if that's possible with 0 ppm, or if any of that makes a difference) and I was shocked how delicious everything was. Since they roast and brew using this water all the time, they had figured out how to make their coffees very delicious using it.

All the other occasions, I've had very bad experiences with ro/distilled..

September 24th, 2018, 2:49 pm

Interesting. I heard long ago that distilled water interferes with the extraction by thickening the grounds, so they feel like pudding or paste. Did they stir the cups or do something to the grinds?

September 30th, 2018, 7:49 am

This calculation seems to be wrong:

Frighteningly, it doesn't take much to get out of range. If, for example, you're using off-the-shelf baking soda, just 0.05g in 1 liter of distilled water will get you about 60 ppm bicarbonate (as CaCO3) - as Goldilocks would say, "just right." But if you edge up to 0.1g in a liter, you've jumped to 120 ppm (as CaCO3), which is probably more than you need in all but the very hardest of waters.

0.05g of baking soda will give you only 30 ppm CaCO3 equivalent, since CO3 is 2- and HCO3 is 1-.

I've had some coffees that taste very good using distilled/RO water too. I guess it more depends on what the roaster uses? Either way phrases like "hard water extracts more out of the coffee, rips everything out etc" are rubbish. If anything distilled water would be a better solvent, however the water composition doesn't seem to affect extraction yield at all.

September 30th, 2018, 4:57 pm

namelessone wrote:If anything distilled water would be a better solvent, however the water composition doesn't seem to affect extraction yield at all.

Interesting to hear that their calculations were wrong.

The water composition does affect extraction. That's basically the whole premise of Maxwell Colonna Dashwood's book. (I would recommend it.) I've spent quite a bit of time playing with waters, and I found that higher GH and higher GH:carbonate hardness waters extract more aggressively (according to refractometer readings).

September 30th, 2018, 7:39 pm

NoStream wrote: I've spent quite a bit of time playing with waters, and I found that higher GH and higher GH:carbonate hardness waters extract more aggressively (according to refractometer readings).

I've not yet seen a scientific study that supports this. It was postulated by the 2014 Hendon et al. study ( https://pubs.acs.org/doi/pdfplus/10.1021/jf501687c ) based on relative binding energy calculations. They did not test the assumption with a refractometer. The recently published SCA Water Quality Handbook (page 23) says this:

Higher total hardness is assumed to increase extraction efficiency (Hendon et al., 2014). In laboratory tests, this effect could not be verified by means of a coffee refractometer, although a clear impact on flavor balance and aroma was detected.

(That handbook is highly recommended - very complete and nicely organized - now available from the SCA store - here: https://store.sca.coffee/products/the-s ... 9334327398 )

The taste experiment of different waters by the same SCA scientists that did the new water quality handbook is interesting but a little hard to find if you aren't an SCA member. Right now you can get an online summary of the study on page 20 of the Caffee Europa magazine - here: http://scae.com/images/caffee-europa/CE61.pdf

This was a blind cupping of three trials by four professional tasters, and involved two coffees, eight attributes, and three different waters of similar composition but filtered to high, medium, and low hardness and alkalinity values. They did see some statistically significant differences in some attribute scores, with the lowest mineral water scoring highest wherever the difference was significant.