I fine-tuned a bias judge for $30. The training was the easy part.

I spent two weeks building judge-from-scratch — an end-to-end pipeline that fine-tunes Gemma 4 E4B into a specialist model that evaluates pairs of responses for social bias. The model is on HuggingFace, and it runs locally via Ollama in 30 seconds. Total bill: ~$30. GPU time: ~2 hours. The data pipeline: most of those two weeks and 25+ documented decisions. That ratio is what this post is about. The task The judge takes a question from BBQ (Bias Benchmark for QA), two candidate model responses,