Provided herein is a process for preparing a mixture including 5-(hydroxy-methyl)furfural (HMF) and one or more HMF esters of formula (I), the process including the following steps: (A-1) preparing or providing a starting mixture which includes one, two or more carbohydrate compounds and as the solvent or as a co-solvent for the carbohydrate compounds an amount of one or more carboxylic acid esters of formula (II); (A-2) subjecting the starting mixture to reaction conditions so that at least one of the one, two or more carbohydrate compounds reacts, and a fraction of the amount of one or more carboxylic acid esters of formula (II) is hydrolyzed, so that a mixture results that includes 5-(hydroxy-methyl)furfural and/or the one or more HMF esters of formula (I), one or more carboxylic acids of formula (III) and a remaining fraction of the amount of one or more carboxylic acid esters of formula (II).