A pinch of salt for your coffee, Sir?


A small sprinkle of salt will suppress bitterness – and in some cases it can benefit the overall coffee flavor. I’ve tried it with an espresso and somehow it works, but it’s difficult to describe the flavor.

I prefer my coffee black, and politely decline when offered milk and sugar. However, if offered salt I would probably smile and say “Yes, please!” Salt???! It turns out that adding salt to coffee is not as weird as it may sound at first. There is a tradition for adding a pinch of salt to coffee in Northern Scandinavia, Sibir, Turkey and Hungary. And when available, such as in coastal areas where fresh water from rivers mixes with the salt sea, one would simply use brackish water when preparing coffee. This water typically has a salt content of 0.5-3%, which is lower than the average 3.5% in seawater. This results in a more intense taste and more foaming. And if living far from the sea, the Swedish food blogger Lisa Förare Winbladh let me know that in Northern Sweden one would deliberately add salt if using melt water from glaciers for making coffee. But tradition aside, is there a scientific explanation of this widespread tradition of preparing coffee with addition of salt?

The first thing that comes to mind is that salt reduces bitterness. And to be more precise it is the sodium ion (Na+) that interferes with the transduction mechanism of bitter taste. But interestingly the mechanism behind this is not fully understood! One of my very first blog posts was about tonic water and how one by adding salt can suppress the bitter taste and make tonic water more or less sweet. It’s a fascinating experiment that you should try at home. Expect to use about 1,5-2 g salt for a glass with roughly 1,5 dL (150 g) of tonic water. It’s a good idea to start with a little salt and taste it as you go.


Try adding a little salt to tonic water – the effect is quite surprising: The characteristic bitterness from the added quinine disappears!

Bitterness is an important flavor in coffee, but under less-than-optimal extraction conditions it can be too dominant. Generally bitter tasting compounds are less water soluble than other coffee flavors, hence the bitter compounds are extracted towards the end of the brewing. High temperatures (close to boiling) and long extraction times also favor bitterness. In that respect the coffee percolator is known to produce rather bitter, over-extracted coffee due to near boiling temperatures, and such coffee would most likely benefit from a little salt! And before the percolator came the ground coffee was just put into the boiling water and then left to settle. I can really imagine how brackish water could actually benefit

But the salt need not be reserved for over-extracted coffee. I’ve tried using salt both in a drip coffee maker and in the filter basked when pulling an espresso. The tests were very un-scientific, but the tiny amount of salt does dampen bitterness and change the coffee taste (but the coffee does not have a salty taste). Since I lack cupping experience, I certainly lack the language to describe how salt influences the taste, so I leave it up to you to try it out! And maybe some baristas with cupping experience can fill me out on this and do some tests?

In stead of just using plain salt with coffee, cured ham would signal rafinesse if served in central Europe, whereas in Northern Sweden there is a tradition for serving dried meat with coffee. The Swedish author Mikael Niemi describes this in his novel Popular music from Vittula:

“… and then the pií¨ce de résistance among all the sweetmeats: a hard, brown lump of dried reindeer meat. Salty slices were cut and placed in the coffee, chunks of coffee-cheese stirred in, and white sugar lumps were held between the lips. And then, fingers trembling, we all poured the coffee mixture into our saucers, and slurped our way to heaven.”

With cured ham, apart from the salt-coffee interaction, one also has the combination of meat and coffee. From previous flavor pairing rounds TGRWT #1 and #5 (chocolate/coffee and coffee/meat respectively) we have seen that coffee and meat in some ways approach each other and are actually a good combination. A secret tip BTW is to add a little coffee to your beef stocks for extra depth and richness – this works because coffee shares many impact flavors with browned meats due to the Maillard reaction.

Now I’m curious – are you aware of coffee-salt combinations in your own country? Please tell me about it! And if you try a pinch of salt in your coffee – how did it taste?

Update: Read about my tests of coffee with salt at Tim Wendelboe’s coffe shop


Some articles that discuss the role of sodium ions (Na+) in suppression of bitter receptors:

Breslin, P. A. S; Beauchamp, G.K. “Suppression of Bitterness by Sodium: Variation Among Bitter Taste Stimuli” Chemical Senses 1995, 20, 609-623.

Breslin, P. A. S; Beauchamp, G.K. “Salt enhances flavour by suppressing bitterness” Nature 1997 (387), 563.

Bresling, P. A. S “Interactions among salty, sour and bitter compounds” Trends in Food Science & Technology 1996 (7), 390. (free download)

Keast, R. S. J.; Breslin, P. A. S. “An overview of binary taste–taste interactions” Food Quality and Preference 2003, 14(2), 111.

In addition to suppression of bitterness, salt can enhance sweetness at low concentrations and umami flavors at higher concentrations (more about this in part 5 of “Practical tips for molecular gastronomy”).

60 Comments

  1. As a teenager (late ’70s) in northern Ontario, I worked in a convenience store where the owner instructed us to add about 1/4 tsp (1 ml) salt to the ground coffee (in a commercial drip machine). She told us it was the secret Tim Horton’s used–Tim’s has since become by far the most popular coffee shop chain in Canada. I don’t know if she was correct, or if she had just found a way to improve the cheap robusta coffee we served.

  2. … or now having done some preliminary tasting of just salted water, I’ll begin with 0.5% tmw (6 grams in 48 ounces of water) and work our way up. I’d not like to see the wrath of my beloved if her first taste in the morning was distinctly salty! Actually this just reminded me of having April Fooled my dad with a sugar bowl full of salt one morning many years ago. Not a happy Dad.

  3. Martin: Very interesting! Perhaps other readers know if this little secret trick is still used by Tim Horton’s? And I’m glad you brought up Robusta, because it might be that salt is better at what it does with some cheaper more average coffee.

  4. My mother once told me that if you use soft water (i.e., with a low content in calcium and magnesium ions, I guess) for brewing your coffee, you should add a pinch of salt to improve the taste. Not being a coffee drinker at all, I never tried this.

    I also read that thousand of years ago in China, tea was more of a soup containing among other things salt, rather than the drink we are nowadays used to.

  5. Also in Finland in the old days people used to add salt into their coffee. I do not know if that is a habit anywhere anymore though. It was also a funny coincidence that we just yestarday had some discussion on this topic among Finnish food bloggers. Martin, your post was perfect timing for us. Thanks:-)

  6. Many years ago my father always added salt to the coffee he served at his restaurant.
    I also noticed that in some non chain dining establishments it was the “norm” to add salt to the coffee before it was brewed.

    An interesting anecdotal experience a couple of years ago I was in Haut (sp) Southern Ireland – I tasted some of the sea water and it tasted sweet…. This “sweet” sensation was again experienced upon eating some really fresh oysters on the half shell… I am not sure it it was mere anticipation or actuality.

  7. Here in Brazil, in Minas Gerais, there is a regional version of café com leite (coffe and milk) that has a pinch of salt, for flavor and for helping in foaming. Sometimes they add corn meal and cheese to it. Tastes good.

  8. Thank you very much for this article and information. And like always, thank you for the scientific aspects to it.

    You inspired me to write once more about Salt and Coffee in my blogs today. Salt is part of my EVERY cup of coffee since some 20 years. Today I experimented with a comparison once more and it is clear.

    A pinch of salt continues to be a must.

  9. Ok, well! 0.5% is *way* too much. (So those folks making coffee with brackish water are drinking really nasty coffee). My wife and I both spit our coffee out and had to remake it. I think I’ll try 1 gram in 48 ounces of water instead.

  10. @ Matthieu,
    both Coffee was being used some 2 1/2 Centuries ago as a soup, just like Tea much longer ago.
    Both drinks have very complex histories and traditions behind them. Many of which have been forgotten, especially in the western world.

  11. I overestimated the amount of salt I used to add–it was more like 1/8 tsp (0.5 ml) to each packet of ground coffee. At the time it was three shakes from a large salt shaker.

  12. It’s a challenge to remember exactly after (good-god!) 30 years. I think the machine was a Bunomatic, the diner-style machine where you pour a carafe of water into the top, the water is heated and drips through coffee and filter into another glass carafe below. We had pre-measured packages of coffee; if they are still the same size today, they weigh 74 g. I just weighed one here at work on our postage meter.

  13. Michael: I also had the feeling that the brackish water with 0.5% salt sounded a little too much… From the picture you see how much salt I added to the basket for a double espresso. It’s to little to weigh with my 0.1 g balance. But eyeballing I’d guess it was in the range 10-20 mg.

    That corresponds to 0.06-0.12% w/w salt on coffee or 0.02-0.04% w/w salt on the amount of water (based on a 50 mL espresso and a 16.5 g dose of coffee).

  14. When I lived in Chile, I added salt to cheap, instant coffee to cut bitterness. Since then, I’ve tried caramel and vanilla salt on lattes. It’s good, yet not my favorite application.

  15. I think that cutting bitterness must be part of the reason for the surge in popularity of dark chocolate combined with a sprinkling of salt, in addition to the bit of sugar.

    Also, the effect in brewing would be dependent on the ph of your water. Here in Hawaii, the calcium is very low and we have acid rain due to the volcano, so for those of us on catchment water, salt or a pinch of baking soda may help in preventing bitterness. I have found the baking soda to help softening when cooking legumes. Also, since I don’t brew coffee, but instead grow and process cacao, finally using a French Press for the finished drink, it might improve with a bit of salt. Will definitely try.

  16. I performed Breslin experiments at a “senses” fair science in 2007, in Buenos Aires, Argentina, and it was a complete success!! I repeated those experiments at several meeting…people are amazed!

  17. Excelent Martin!

    Many people do that in Spain. I did it frequently years ago, but I’m not sure whether I was convinced it worked or it really worked.

    I’m quoting-translating your post in the next one in my blog, if you don’t mind

    By the way, I did not see you in Brugge!!! It was a pity. It would have been nice to meet again. Nest time I will contact you first.

    Cheers

  18. in France (south) they use to give salted coffee to counter hangover, that was 45 years ago, i was a kid then and felt sooo sorry for those who had to drink the mixture, first they obviously felt bad from overconsummation of alcohol, then having to drink coffee, awful, but with salt ! After my teenage years, i cant remember i ever heard of it again.

    now i like coffee, and i might try to add some salt, even i must say that i feel chicken skin just thinking about it, so strong is the prejudice but one has to try not to die an idiot

  19. My mother in law taught me the trick of putting a pinch of salt into a coffee as it brews. Its what turned me into a coffee-phile! I put a pinch in my coffee every morning (with about .02%-.05% ground cardamom) in my percolator. It’s hardly my perfect brew, but it definitely gets the job done in the morning. I brew a fine ground espresso blend in my drip machine, I add about 1/2 the suggested portion of 60g per 200g of water since its finely ground, and an espresso blend) for my morning brew. I’m glad to see some research on this, as many of my coffee-phile friends aren’t familiar w/ the salt trick (most of them brew coffee correctly, so its not surprising). My afternoon brew, I bring a french press to work with me, grind the beans on a medium ground, and brew with 180 degree water for 4 minutes, w/o salt.

  20. Wow – that’s amazing. It seems as if it’s something many do, but don’t talk much about? Summarizing what I had heard before (+ some private email correspondence) and your comments I have the following list of countries were salt is added to coffee:

    Argentina, Brazil, Canada, Chile, Ethiopia, Finland, France, Norway, Spain, Sweden and USA (including Hawaii)

  21. I’m thinking to launch it as a new fashion in japan where i live now, Japanese people are extremely curious about new tastes, and i heard sometimes people complaining about the bitterness of coffee, but would never have thought suggesting the pinch of salt…

    What is interesting is the wide geographic differences between the countries where the pratice is known.

    In France, outside of as a counter for hangover, never heard about it, and never outside my own countryside.

  22. vry interesting idea! as u write, there r many factors that can affect the bitterness of coffee especially with espresso, b4 resorting to salt as the solution to bitterness, i would highly recommend alternating and trying a different technique(s) to achive a non or less bitter coffee. well poured espresso should be rich, sweet, balanced and slightly acidic! NEVER BITTER

  23. To me, it looks like you used iodized salt in that picture, which kind of makes me cringe. I think the flavor of the iodine would bother me so much that i’d prefer bitterness.

  24. Neil: Yes – I used iodized salt (do you recognize it from the shape of the crystals?). However, I don’t think you should worry about any iodine flavor. First of all, it’s not elemental iodine which is added to salt. The common salts to use are potassium iodide (KI) or potassium iodate (KIO3). The salt I have contains 0.5 mg potassium iodide for every 100 g salt. Thats only 5 ppm (parts per million)! It’s true however that the iodide (I) can be oxidized to iodine (I2), especially under hot and humid conditions. Elemental iodine is quite volatile and sublimes, meaning that it passes directly from the solid state to gas phase. This means that iodine will never really accumulate in your salt box. It will probably diffuse out of the box at the same rate as which it is formed.

    Apart from that the amount of potassium iodide is really tiny. Assuming that the dose pictured above in the espresso basket is 10 mg salt, that corresponds to 0.00000005 g of potassium iodide which is equivalent to 50 ng (nano grams). In a 50 mL espresso that corresponds to a potassium iodide concentration of 1 ppb (parts per billion) or 0.001 ppm. This is not much, but at the same time it’s really difficult to have a feeling for such small quantities as our nose is also very sensitive to certain smells.

    For the sake of the argument, let us therefore assume (no matter how unlikely) that we oxidize all the iodide to iodine. In that case our coffee would only contain 38 ng of iodine, which would correspond to a concentration in the espresso of 0.76 ppb (= 0.00076 ppm). The number doesn’t really mean much by itself, but I found some threshold values for iodine in the litterature (http://jds.fass.org/cgi/reprint/46/8/799.pdf). These are the lowest detectable amounts of iodine in: tap water (0.06-0.08 ppm), skimmed milk (6-8 ppm) and whole milk (10-14 ppm). As you see, even if all the iodide in the salt suddently were oxidized to iodine, we are still two orders of magnitude below a detectable amount of iodine in water.

  25. i read last night in “the hunt for red october” by tom clancy: “it was traditional coffe navy cofffe, brewed strong, with a pinch of salt.”

  26. I have long suspected some of the “better” espresso bars here in Brisbane (Queensland, Australia) salt their coffee (though until now I had guessed it was going into the milk). Can anyone verify this? I once asked a barista about the saltiness of the flat white he served me. It was really so obvious that when he said he couldn’t taste it I assumed he was lying!

  27. I live in Belgium and we’ve always added chicory root to our coffee (it also serves as a coffee substitute, but I wouldn’t recommend it). Apparently it’s a pretty common practice down in the mediterranean as well. I’ve been instructed to use salt before when we were out of chicory. For salt I drop a pinch in the filter of our percolator, for chicory you need a bit more, bout half a table spoon for every 5 table spoons of coffee.

  28. C O L O M B I A !!! My father talks of adding cheese to hot coffee, where it sank to the bottom in a chewy, melted mass of goodness and then they eat it with bread or grilled corn patty. The salt he said was added when there was no money for cheese and the salt made up for the lack of cheese! So PLEASE add COLOMBIA South America to the list!! Martin, I how funny to think all these people are quietly salting their coffee and not sharing the dark little secret!! Cant wait to try…fluer de sel maybey?

  29. I don’t know about coffee, but adding a bit of salt to rice milk takes away that sickly sweet flavor and makes it almost taste like cow milk.

  30. I guess you could add America to the list – at least I know of one person who has been doing it for years.
    One point, as Jonathan Mendez also mentioned, is that the coffee is brewed with salt, rather than the addition of salt post-brewing . I’m told there is a difference in flavor. This suggests that the ionic strength of the water plays a role in the extraction process and the difference is not simply at tasting.
    It would be good to see GCs of the same coffee brewed with salt and with salt added post-brewing.

  31. I was reading an old mystery novel the other day and the main character (who is depicted as a bit of a chef … or at least a good cook) puts a pinch of salt in his coffee grounds before brewing.

    In other words, a few scoops of coffee and a pinch or a dash of salt.

    I’m actually squeamish to try it … sounds icky … but I’ve been wrong before.

    Does anyone routinely put a dash of salt into their coffee maker when brewing coffee?

  32. My 1960ish “Margriet” cookbook (then one of the popular cookbooks for the housewife in the Netherlands) has an interesting recipe for drip coffee:

    Grind coffee finely, add to filter, add a pinch of salt. Compact the coffee, add 2 or 3 tablespoons of lukewarm water. Cover the filter & leave for half an hour. Then slowly add hot water until the the coffee runs very light brown.

    That’s right, a 45 minute recipe for drip coffee. I’ve never tried it. Anyway it seems at least that adding salt wasn’t unheard of in the Netherlands. I’ve never seen anyone do so, though.

  33. VERY interesting although not surprising now that you’ve mentioned it. Salt draws out the flavours of whatever you put it on – I love it with watermelon. I will try this the next time I make a coffee as I don’t like my coffee bitter. Thanks!

  34. A friend of the family who ran a coffeeshop in Vietnam says that he always add a drop of nuoc mam (fish sauce) to his coffee. Sounds like it’s the same idea, just adding salt and meat flavor in one STRONG drop.

  35. @Martin
    I think wds refers to dried and roasted chicory (latin: Cichorium intybus var. sativum) mainly used as a coffee substitute around the world. In Denmark it was common after WW2 when the coffee was rationed.
    I’ve just gotten back from a few months in Asia, and I was very surprised to see that the most common brand of instant coffee in India, Nescafé Sunrise, contains 30% chicory.
    Nestlés Indian homepage has this marketing-speak-overly-positive description of the “sunrise” coffee:
    “NESCAFí‰ SUNRISE Premium is an Instant Coffee-Chicory mixture (Coffee:Chicory = 70%:30%).

    A fine blend of Arabica and Robusta beans is specially granulated to retain its fresh aroma and flavor, giving you an incomparable coffee experience.”

    (“incomparable coffee experience” and “instant coffee” — well, to give them credit, drinking coffee has given me an incomparable experience, but nothing I’d classify as good)

    Robusta beans and chicory — we might have a connection here. According to Wikipedia ( http://en.wikipedia.org/wiki/Chicory ), chicory contains up to 20% inulin (Danish Wikipedia says 13-20%), a polysaccharide that’s also used as an industrial sweetener, so addition of chicory might just be to take the edge of the taste of cheap beans.

    The addition of chicory to coffee in India might be of different reasons from post-WW2 Denmark, as India has long traditions of use of herbal concoctions known collectively as ayurveda or ayurvedic medicine, and it seems that the inulin in chicory has some health benefits as it “increases calcium absorption and possibly magnesium absorption, while promoting the growth of intestinal bacteria.” (paragraph from http://en.wikipedia.org/wiki/Inulin )

    Of course, these are just my ramblings, but I’m tempted to try experimenting with roasting and grinding my own chicory root.

    On a sidenote, chicory (danish: cikorie, norwegien: sikori) is also used as salad, known in Denmark as “julesalat”…

  36. I grew up in Ohio and from the very early 1960’s, remember my Mom putting salt in the coffee every time before brewing it. She was of German heritage and my Dad was of Irish heritage. She always made the BEST coffee, and this is possibly the reason why!!!

  37. I’ve been in the business for several years, and this is the first time I’ve heard of adding salt to espresso! Feel a but silly now, looking at the rest of the comments 🙂

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