In the book "Last Dinner on the Titanic" the coffee is mentioned only briefly and here's what it says:
"On board the Titanic, coffee was probably made by a drip process, although the much stronger Turkish coffee may well have been available in first class. Either way, coffee was typically accompanied by cigars, port, and liqueurs, then called "cordials". Often the liqueur was poured straight into the coffee, which meant the cups were served only three-quarters full."
Not really much there about the coffee, but I thought this might help.