Tomorrow I will try brewing with only distilled water, and wanted to start a discussion on it.

First, why I want to try it. I have been using Third Wave Water (TWW), as instructed with one packet per a gallon of distilled water, for the last 12 months. Most coffees have been flat sweet and some chocolatey even though I brew African coffees primarily.

I have read that less TDS will extract more. Also, I have found that some indicate even though right at the SCA recommendation, TTW is too high in TDS at ~150ppm with some saying it is really near 180 to 220 effective range based on electrical charge - I am not a chemist, so that is my paraphrasing. Also, I found an article where many different waters were tested and the testers gave the highest marks for all three attributes, sweetness, acidity and viscosity to brews using distilled water. Here is that article: https://dailycoffeenews.com/2018/08/29/ ... sory-data/

Recently I have been brewing Wendelboe's Nacimiento Bourbon. My first several brews were in a V60 using normally prepared TWW. It was very good coffee but more traditional tasting than the advertised tasting notes. My first brews, using normal TTW, were creamy rich, smooth with overall sweetness like hot coca. Unless someone watched me preparing it, one, especially if not accustomed to specialty coffee, would be convinced probably that it had some kind of cream and sweetener in it. Per the roster's notes it should be winey, floral with tastes of forest berries.

I did a review of it on Reddit - Coffee. Someone suggested it might be the water as to the reason why I was so far from its roaster's tasting notes. When I replied I was using TTW, the advice was to dilute it in half. I did that today and the coffee was floral and winey with a fainter sweetness that was more tart-fruity. Very good coffee and fairly different than my other brews - had I not know the water was different, I would think it was a different coffee bean.

After that, I want to now try straight distilled to see how different it will be, but all this is confusing to me. With many articles stating less TDS makes for more extraction, I would think lower TDS would make coffee more traditional, richer, smoother and creamier, not more bright as it seems to do. Do the articles have it wrong, and lower TDS creates less extraction? or perhaps the extraction is higher but taking more of the bright compounds?

Tim Wendelboe is very well-known for extolling Oslo's very soft water. Using water similar to the water that the roaster used to develop the roasting curve should give better results - about 10 years ago Phil&Sebastian (top Canadian roasters) found this out, albeit from the other end: https://www.freshcup.com/correct-coffee-wrong-water/

Interesting cupping results in that dailycoffeenews.com article. Distilled seems to be the clear winner, but they stop short of announcing it as such.

I'm using reverse osmosis water for pour-over. For espresso I use RPavlis recipe, which is the same + a tiny amount of potassium bicarbonate. It can't get any simpler than this, and the results in the cup are great.

Miss-post

Where I live the water is fairly similar to Oslo's - only with less metals.

I have just started experimenting with filtered water and adding back sodium bicarbonate and/or magnesium sulfate in different amounts. So far it has mostly turned out worse than tap water. I guess I should just try straight filtered water - guess it's gonna be quite acidic

Thank you for the article, I will definitely try calcium chloride as well now.

One thing I have noticed is that sometimes my preference will change depending on the temperature of the brew. For example today's brew with tap water and some additional magnesium sulfate was quite bad when hot, but with a vibrant acidity as it cooled down.

How long does water stay good? Is there an expiration period?

Our water is very soft, less than 100ppm, quite tasty as drinking water straight out of the tap. We're lucky. Where I used to live I regularly lugged multiple five gallon jugs of R/O water from a water store. Now wonderful water just flows out the pipe.

But sometimes, on vacations, I've really had the sense that the harder water in the locations I was visiting improved my coffee. And right now in the cupboard I have a bottle of local tap water from one of those vacations where my hotel Aeropress coffee just shined brightly. I brought that bottle home intending to do some sort of taste test but instead forgot it was even there. It's been a few years now. Is it still worth brewing with it and comparing to our tap water?

I would not use water that was put into a non sterile bottle a few years ago.
https://www.cdc.gov/healthywater/emerge ... 0it%20well.

I use distilled with a little bicarb and CaCO3 added back in. Way less that SCA recommends.

The CDC says you can disinfect water by boiling it, which I would do anyway. Aside from possible microbial contamination what might go "off"?

Brewing with distilled water it's kinda rare experience for me but there's 1 local roastery good with soft water around 14-17ppm.
Regarding the TWW/Aquacode I also using daily but with lower ppm I dillute to 5L/sachet it gives around 115-120ppm.
Most of the time it's quite okay with Ethiopia, Kenya, Rwanda beans, for local Indonesia coffee I dillute more to 75-85ppm it's a bit trial and error...

First, this is not related to espresso it is related to pour-over only. I think espresso could be quite different in regards to water from the taste aspect and equipment issues. For pour-over (V60), I have found by experimenting that you get more extraction and flavor with higher levels of hardness (primarily calcium). It is a known flavor extractor. On that point, I don't buy the distilled or very soft water being superior (it may be for espresso where the water to coffee ratios are drastically different). Another big factor is alkalinity. My total hardness is 162 ppm as CaCO3 with calcium at 43 ppm. My alkalinity was 109 ppm as CaCO3 which I thought was high even for pour-over even though I was getting pretty good results. So I experimented with reducing alkalinity and obtained best results around 85 ppm as CaCO3. This still seems high but I believe it has something to due with the ratio of hardness to alkalinity. If I had softer water, I would probably find that the alkalinity needed to be lower. Anyway, I like the harder water with good amounts of calcium and the adjusted alkalinity for pour-over. I can't comment on your TWW results but I may try it. It does give pretty hard water but I think the magnesium is the primary hardness component.