What angle should the glass be at while pouring beer from a bottle?

Pouring beer from a bottle at an angle of 45 degrees is optimal for achieving the right balance between creating a good head (foam) and minimizing excessive agitation of the beer. This angle allows the beer to flow smoothly into the glass while maintaining a controlled introduction of air, which helps to develop the beer's aroma and carbonation.

Pouring at 45 degrees allows the beer to run down the side of the glass, which is gentler and less likely to agitate the beer too much, helping to prevent over-foaming and ensuring that the beer's carbonation remains intact. As the glass fills, it can then be gradually uprighted to adjust the pouring angle to direct the beer more towards the center of the glass, where it can create a proper head.

Other angles typically do not provide the same balance. For instance, pouring at 90 degrees may result in excessive foaming, leading to a poor drinking experience, while a 30-degree angle could lead to a similar issue with increased agitation. Pouring horizontally would not be effective for filling the glass and could lead to spilling, making 45 degrees the most advantageous angle for pouring beer correctly.