My grandfather-in-law was born in England in the 1920s and fought in World War II. Somewhere along the line he acquired the habit of salting his beer before drinking it, which persisted for the rest of his life. I'm as curious about the cultural genesis of the practice as the food science of it – was there perhaps something about wartime beer that made it unpalatable without salt? I know there were other wartime food customs like bread and scrape so it doesn't seem implausible, but the "why" of this one isn't so obvious.
I can think of several reasons why you might salt beer:
- Salt is a natural flavor enhancer, so you'd be able to taste the hops and malt more
- Salt reduces perceived bitterness, so overly hopped beer would taste less bitter
- The salt crystals may nucleate bubble formation, giving the beer more head (briefly)
I've heard of it being done before, but never with good beer, only low quality swill. But then, since there were more quality problems with cheap brews at the time, this was probably a lot more common.
There are circumstances where working in a hot place will make people sweat so much that they need to take salt to avoid a deficiency. I first heard mention of this from a man who had been doing field work in the Blue Mountains of Queensland, then found out more when working in a metal foundry, after which I worked in a factory where salt tablets were made.
Most people take their salt in tablet form, sometimes the tablets dissolve in water to give an effervescent drink. A salt deficiency can commonly cause very unpleasant muscular cramps, among other things that can happen is a state that resembles drunkenness (but without euphoria).
I have seen foundry workers put a dash of salt in their coffee, if you go back in history you find that salting coffee happened in the 18th century coffeehouses.
My guess is that the man in question had at some time in his life worked in a hot place, where it was necessary to take more salt because of sweating. That might have been, say, North Africa during WWII, or a metal foundry in a temperate place. Then he got the taste for salting his beer and carried on doing it, after he stopped working in that hot place.
As other answers have noted, salt enhances flavor and reduces perceived bitterness. It also increases the perceived body/mouthfeel of the beer.
My grandfather always salted his cantaloupe and honeydew melons. I tried it, and was pleasantly surprised by how it intensified the melon flavor.
Also of note is Gose, a style of beer brewed in Leipzig, Germany. It includes coriander and salt.
This reminds me of a story my grandfather told me: in the Netherlands, right after the war, there was a great deficiency of many kinds of grains, which made the beer taste bad. The bartenders of the more upscale cafes would put a slice of lemon in the beer to mask the bad taste. This habit stuck, and we still do it today.
No idea how much truth there is to the story (my granddad being quite the storyteller), but perhaps it can shed some light on this question.
In my younger days I would perspire at the mention of the word heat. I never thought about adding salt to replenish what my body had lost, I just did it because it seemed to make the beer less bitter and enhanced the taste. Besides, none of my buddies did it, so I felt unique. It was something I picked up from my grandfather and father (I never could force myself to do the raw egg in your beer, though).
Salt releases the carbonation. More bubbles in the beer. That gives it better flavor for many. Or some salt on the edge of the mug. You do not see that as much today. Often years ago kegs would loose some carbonation. Or the beer would go some what flat. This restored the carbonation. Then you can get use to the little extra salt taste. Salt helps cut the dry out of the mouth if working hard. Like bucking bales for a 1/2 day then a cold beer was part of your lunch. A little salt cuts thirst. In the 50s it was more common to see this in small towns around farmers. A pinch of salt in beer. But not in the big cities. A person of his times.
My grandfather salted his beer. I never asked him why. He was a coal miner in west Virginia. I salt mine too, only because he did. Kind of like carrying on a tradition. I notice it does make it bubble a bit. Someone told me that it removes gas from the beer so you get less gas. Nothing worse than beer farts. Haa.
Ether way, it always makes conversation at whatever table I drink at. everyone says something about it. and they all enjoy seeing the extra bubbles.
As a man whose survival relied most on his physical condition, he couldn't afford to dilute his body's supply of minerals by increasing the volume of salt-less bodily fluid and leaching said minerals from inside his cells to achieve equilibrium before peeing everything out. Lack of salt causes cramps, delusions and fatigue. People can survive like this when there is no threat and social rules are in place for protection, but in wartime? No. Beer has calories and is sometimes safer to drink than water, but extra salt would ensure that the fluid could stick around and be used. It takes 9 grams of sodium per liter of water to make an isotonic solution. 9,000 milligrams are required to be the same concentration of sodium as is typically found throughout bodily fluids. Cheers!
My step-dad (passed long ago) served in the Philippines back in the Korea/Vietnam era. I asked him one time why he salted his beer. He said the beer he drank in the Philippines was very poor quality and adding a little salt made it palatable. He continued to do it as it became an 'acquired taste'. I tried it... it ruined a perfectly good bottle of beer. Of course, I haven't been able to find Ritterbrau anywhere since, either. But, then, Ritterbrau is an acquired taste, too.