Default
Default. Coffees: Confidence adj. (light). Other boards: Average (3+ bags).
Average
Raw average.
The average of each bag's rating; a bag counts once, weighted by its rated brews (n/(n+2): 1 brew a third, 4 brews two thirds, 10 brews 0.83), so a sachet brewed once can't outvote a full bag. Bags at 9 (10 brews) and 6 (1 brew) → 8.1. A one-bag roaster at 9.5 ranks above them.
Average (3+ bags) (default for other boards).
The same average; rows marked Low confidence are left out: coffees with under 4 rated brews, groups under 3 bags or 10 rated brews. A one-bag roaster at 9.5 is not listed; a 3-bag, 12-brew roaster at 8 is.
Confidence adj. (light) (default for Coffees).
Adjusted for confidence: the average pulled toward your overall average, as if every group had 2 extra bags at that average (light). A coffee (one bag) gets 2 extra brews instead, so one lucky brew can't top the board. A roaster's one 10-brew bag at 10 → 7.9; four at 9.5 → 8.6. A coffee at 9 over 6 brews → 8.5.
Confidence adj. (strong).
The same, with 5 extra bags, or 5 extra brews for a coffee (strong): small groups stay close to your overall average. One 10-brew bag at 10 → 7.4; four at 9.5 → 8.0. A coffee at 9 over 6 brews → 8.1.
Peak
Best brew.
The highest single brew rating in the group. Brews of 8, 9 and 10 → 10.
Best, conf. adj. (light).
The best brew, pulled toward your overall average as if you had 2 extra brews at that average. A score hit repeatedly counts for more than a single lucky one. One 10 → 8.0. Four 9.5s → 8.7.
Best, conf. adj. (strong).
The same, with 5 extra brews. One 10 → 7.5. Four 9.5s → 8.1.
Examples assume your overall average is 7.0.