Doctor Johnson’s biographer, James Boswell, is commenting on Johnson’s thoughts on friendship.
I have often thought, that as longevity is generally desired, and I believe, generally expected, it would be wise to be continually adding to the number of our friends, that the loss of some may be supplied by others. Friendship, ‘the wine of life,’ should like a well-stocked cellar, be thus continually renewed; and it is consolatory to think, that although we can seldom add what will equal the generous first-growths of our youth, yet friendship becomes insensibly old in much less time than is commonly imagined, and not many years are required to make it very mellow and pleasant. Warmth will, no doubt, make a considerable difference. Men of affectionate temper and bright fancy will coalesce a great deal sooner than those who are cold and dull.
From “Life of Johnson by James Boswell
This seems to be Boswell himself, not reporting Johnson’s words; Johnson was famously melancholy but had many friends whom he helped in different ways. Johnson was a great tea drinker, though also had a notable capacity for drinking wine.