"What's the difference between the neutron bomb and East German mixed-blend coffee," an East European diplomat asked a colleague here recently.

"While both destroy people," the diplomat continued, "the coffee destroys the cup and saucer as well."

Like much of the subtle humor in Eastern Europe, that joke now making the rounds of the diplomat quarter here carries with it some important social commentary.

Indeed, a visitor to the eastern sector of this divided city these days quickly discovers that the crowds peering into store windows are looking mostly at one thing - the daily price of coffee.

Inside the stores, the main topic of coversation seems to be the skyrocketing cost of good coffee - now about $14 a pound - and the poor quality of the new, lower-priced, so-called mixed-blend varieties.

What is most important, however, is that the best and cheaper coffee in town is unavailable to most East German shoppers.

This combination of annoyances to the average East German coffee drinker is not trivial. In fact, it adds up to a touchy political challenge being brewed for the leadership here.

The best imported coffee is available here at about $4 a pound only in a string of stores known as "Intershops." These stores are widespread throughtout Eastern Europe, especially around major cities and tourist centers.

The rise in the price of coffee has simply served as a catalyst to focus the attention of both the average worker and of East German President Erich Honecker.

Sone things have happened here recently in connection with these issues that are remarkable for a country as rigid as East Germany.

For example, numerous sources here confirm that a team of workers from an East Berlin electrical firm recently demanded that 20 per cent of their wages be paid in West German currency. They claimed that since they were involved in exporting, the products they turned out earned Western currency for the state and they should share access to it.

Though the petition was rebaffed, the message was apparently heared in high circles.

In a speech in Dresden late mont, Honecker was forced to take note of the growing grass-roots resistance to the Intershops among some people and to concede that "these shops, of course, are no standing accompaniment to socialism."

Honecker defended the need for the shops as a means to gain hard currency, and pointed out that East Germany had to lay out some $300 million last year just for imported coffee.

To try to improve accessibility to hard currncy. Honecker said the state would start putting more imported products into another state-run chain known as "Exquizit-Shops," where goods can be brought for East German marks, but at much high prices.

Though the East Germans charge people the same exchange rate for East German currency is virtually worthless outside of East Germany.

As another step to appease coffee drinkers, the state also started marketing the mixed blends at a lower price with some substitute components. These are said to so bad that they can't be processed in coffee-making machines.