Why do homemade liqueurs sometimes taste bitter or too sweet?

Expanded Explanation

Homemade liqueurs often taste bitter when ingredients have been over-extracted, when too much citrus pith is included, or when strong spices, herbs, coffee, or tea have been left in the alcohol too long. Bitterness can also come from over-roasted nuts or burnt sugar notes that are stronger than expected. In small amounts, bitterness can add structure, but too much makes the liqueur harsh.

A liqueur becomes too sweet when sugar is added too quickly or in too large a quantity before the flavor has been properly evaluated. Sugar can make a young liqueur taste pleasant in the short term, but it may flatten fruit, blur spice, and leave the finish heavy or cloying after resting. Sweetness should soften and support, not dominate.

Both problems come down to balance and timing. The best way to avoid them is to taste during infusion, sweeten gradually, and allow the liqueur to rest before deciding on final adjustments. In many cases, bitterness can be controlled by shorter maceration, and sweetness can be improved by making small syrup additions instead of one large correction.