In Comtrade, data availability is based on commodity classification. From your question, it seems that you query only HS2002, which started in year 2002. If you want to query longer time series, you have to use older classification. But first, you have to know what commodity codes to be used in previous version of HS.

For an example, HS02 codes 090111 [Coffee, not roasted, not decaffeinated] has the same code for HS96 or HS92, so you can use code 090111 and classification HS92 to query data from year 1988 (HS92 starts on 1988).

For longer time series, you have to use SITC classification which started in year 1962 (first revision). Because you want data from 1985, SITC Rev.2 can be used (started in year 1976). The code HS-090111 corresponds to S2 code 07111 [Coffee, not roasted; coffee husks and skins]. However, from the description, it is not exactly the same with 090111.

If you want just to have coffee in general, you can use higher digit code, such as 3 digit SITC Rev.2 code 071 [Coffee and coffee substitutes]

http://comtrade.un.org/db/ce/ceDefault.aspx?Page=1&Phrase=coffee%20AND%20SITC.2%20and%20071