Lemons are not typically described as sweet or bitter. They are primarily known for their sour taste, which comes from their high citric acid content. While some may perceive a slight bitterness from the lemon rind, the dominant flavor is sourness.
The perception of bitterness can vary depending on individual taste preferences, the ripeness of the lemon, and how it's used. For example, preserved lemons can have a more pronounced bitterness due to the fermentation process. Additionally, the bitterness of lemon rind is often used in baking, adding a complex flavor dimension to dishes like lemon bars and marmalades.
In summary, lemons are primarily sour, with a subtle bitterness that may be more noticeable in certain preparations.