It happens to all of us at some time. That beer that you wanted brown is copper instead or maybe your stout is just a shade more brown than black. What's a light in the color brewer to do? Do what the Germans do and make up a homemade batch of Sinamar, which is a Weyermann malt extract product used to adjust color.
To produce your own, soak a pound of Carafa malt in a quart of cold water for 24 hours. Strain the mixture through cheesecloth, a fine mesh strainer or a coffee filter. The resulting black inky mixture can be saved in a sanitized jar for over a month.
To use your new color extract, carefully pour a small amount into the brewpot, stir and pull a sample to look at the color. Keep adding small amounts of colorant until satisfied. tpb