This paper presents a domain-specific transformer pipeline for quantifying social atmosphere in hostel reviews, an experiential dimension that travelers consistently prioritize but that existing NLP methods and booking platforms fail to capture. We train a cross-encoder on 4,994 manually annotated reviews and use it to pseudo-label 162,840 additional reviews; these labels are then distilled into a sentence-transformer bi-encoder, producing embeddings where proximity reflects social interaction level rather than generic sentiment. On held-out human-labeled data, the domain-adapted embeddings achieve F1 = 0.826, outperforming generic sentence embeddings (0.671) and zero-shot GPT-4o (0.774), with a 40-fold improvement in intra-class versus inter-class similarity. Aggregating predictions to the property level reveals that hostel socialness follows an approximate exponential distribution, confirming that highly social hostels are rare. This work formalizes socialness as a measurable semantic construct and provides a general template for extracting implicit experiential attributes from text at scale.