BB,
Have a look at the engineers site airmech there was apparently 8000 kgs of fuel. I doubt whether coffee could penetrate the conformal coating of pcb's and the like, unless they are overheated. Let's all accept the AAIB initial report, they are looking at the reasons for the apparent electronic control of both engines not increasing thrust when demanded. If that has been eliminated I am sure they would have made a statement by now. My concern is that whatever caused this incident may not have been recorded in the FDR because the relevant parameters have not been included.