Waiting for the expected completion date when brewing beer is important for several reasons:
- Fermentation Completion: Ensuring that the fermentation process is fully completed is crucial. Yeast needs time to convert sugars into alcohol and carbon dioxide. If you bottle or keg the beer too early, the fermentation might not be finished, leading to over-carbonation or even exploding bottles.
- Flavour Development: Beer flavours develop and mature over time. Allowing the beer to ferment and condition for the full expected period ensures that the flavours have time to blend and mellow, resulting in a more balanced and refined final product. Rushing the brewing process can lead to off-flavours. For instance, if the beer is not given enough time to ferment properly, it can retain unwanted flavours
- Clarity: Given enough time, suspended particles in the beer, such as yeast and proteins, will settle out. This leads to a clearer beer. Rushing the process can result in a hazy or cloudy beer.
- Carbonation: If you're bottle conditioning (adding a small amount of sugar before bottling to carbonate the beer naturally), it's important to ensure that primary fermentation is complete. If there are still fermentable sugars in the beer, it can cause over-carbonation or potential safety issues.
By waiting for the expected due date, you ensure that the beer is properly fermented, conditioned, and ready for consumption, leading to a higher-quality and more enjoyable final product.