Why Clear Whey Foams
Foaming is a natural, normal, and generally positive characteristic of quality whey protein powders that indicates purity and high protein content. 
Protein Properties: Protein molecules contain both water-loving and water-repelling parts. When shaken vigorously, air gets trapped, and these molecules rapidly surround the air bubbles, forming a stable foam or froth.
Lack of Additives: Products with fewer artificial anti-foaming agents and thickeners tend to foam more.
Hydrolysis: Clear whey is hydrolyzed, meaning the protein is broken down into smaller peptides, which can affect how it interacts with air and water compared to traditional whey concentrates. 

How to Reduce the Foam
The foam is harmless and safe to consume, though it can cause minor bloating due to swallowing air. Here are some common methods to minimize it: 
Let it Settle: After shaking, simply let the mixture stand for a few minutes (around 15 seconds to several minutes). The foam will naturally dissipate on its own.
Mix Gently: Instead of shaking vigorously in a shaker bottle, try stirring slowly with a fork or spoon to avoid introducing excess air.
Prepare in Advance: Mix your shake a good amount of time before you plan to drink it (e.g., before your workout) so the foam has time to settle.
Add an Ice Cube: Some users find that adding an ice cube to the shaker can help reduce the foam a bit.
Use Oil (Caution Advised): Some food science forums suggest a drop of food-grade oil can act as an anti-foaming agent, but this is a less common at-home method.