The GF30 doesn't heat your beer directly — it heats the space around it instead.
Where the heat comes from: a 30-watt, 12V heating element sits in the cavity between the fermenter's outer body and its inner cone.
How it actually warms your beer: rather than a typical element that touches the liquid directly (like a kettle element), this one heats the air/space between the fermenter walls. That warmth then transfers through to the beer inside — similar to how a temperature-controlled room warms whatever's sitting in it.
Why it's designed this way: it means your beer isn't heated from one small, concentrated point — it's warmed evenly and gently across the whole vessel, which is gentler on the beer and avoids hot spots.