If the sauce is not thick enough, reduce it on a high flame, uncovered, just a few minutes, (watch this stage, making sure the liquids don't evaporate) until it reaches the consistency of maple syrup. (levanacooks.com)
If it is too thin, cook it over high heat until it is reduced and thickened to the consistency of maple syrup. (levanacooks.com)
Turn the heat up to medium - high and continue to cook syrup until it reduced by half and thick in the consistency of maple syrup, about 4 - 5 minutes. (hungryrabbit.com)