One word of explanation. The article from which this excerpt was extracted is about how people are slaves to convention.
The canary-coloured footman could not believe his ears; placing his artificially aged head upon one side in the too intelligent fashion of the bird whose plumage he had borrowed, he said: 'I beg your pardon, sir: I did not catch what you said.'
Our oriental friend had been accustomed to be obeyed, and that instantly. 'Pale ale,' observed he a little louder; and then added, sotto voce, some Indian ward which might mean, 'you ludicrously attired and grimacing idiot.' The canaried one, imagining that this unheard end of the sentence must be very important, again put himself in the attitude of obtrusive attention, and every eye at table became involuntarily directed to himself and my unhappy friend.
'Beer!' exclaimed the Indian hero in a voice that has been often heard above the din of battle, and the medals upon his manly chest clashed together as he spoke in rage.
'Conversation,' observed he, in narrating to me this hideous experience, 'entirely ceased after that fatal word. Even her ladyship, justly celebrated as she is at the head of a dinner-table, failed to lift it. Everybody waited until I should get that Beer. Johannisberg could have been procured by the gallon in that stately mansion, but of the simple liquid which I had demanded, there was not a pint in the house. I ought to have known better than to ask for it, but I had just returned from a land of liberty, which I hope was taken as my excuse. The canaries flocked together and chirped apart; then the butler was consulted, who had been staring right over his master's head in sublime indifference to the calamity which had befallen me. He gave some majestic order. I know he did, though I was ten seats away from him, and had my eyes fixed on my plate. It was one of those awful moments when, like a hare, one sees with the back of one's head. I was clairvoyant to everything that was done both in the room and out of it. I heard the area-gate 'go,' as some female servant rushed out with a can to the public-house; I know she had a can because it tinkled against the railings in her haste, and sounded as distinct amid the stillness of the table as if it had been Westminster chimes. . . . It came at last, but I had no desire for it then. It tasted to me very unlike pale ale. Perhaps the butler had ordered them to fetch some inferior article—that which is called "Twopenny." His lordship observed most good-naturedly : 'Come, Sir William, you shall not have that all to yourself: I must take a little too. I am sorry to say that the good old fashion of beer-drinking is going out" But I am quite sure he didn't like it. I have gone through a good deal, but the whole thing forms one of the most dreadful experiences in my life. If I was Mr Thackeray, I would write a Roundabout Paper about it, that would move you to tears.'
'Yes,' said I, 'or if you were A. K. H. B., instead of being only A K.C.B., you might write an essay "Concerning the asking for Beer at a Dinner-party in Belgrave Square."'
Since my friend is neither of those-two famous personages, I have done it myself."
"Chamber's journal of popular literature, science and arts, vol. 19", 1863, pages 50 - 51.
This anecdote tells us much about British society of the period. And the differences in the way the genteel classes behaved in India and in Britain.
It's clear that in India it was totally normal to drink Pale Ale at a posh dinner party. Whereas the upper classes in Belgravia didn't have a drop of beer in the house. The fear and embarrassment of the old colonial soldier demnstrates the power of social convention. He was a hardened soldier, yet was terrified of the butler and his disapproval.
The link with the previous article? Thackeray's Roundabout Papers, mentioned here and the source of the other article.