/tags/temperature/Recent content in Temperature on FermentHiveHugoen-usMon, 30 Mar 2026 12:04:00 +0100/fermentation-science/fermentation-temperature-control-guide/Sat, 04 Apr 2026 12:04:00 +0100/fermentation-science/fermentation-temperature-control-guide/<p>In the Nara period (710–794 AD), the sake kura breweries surrounding Heijō-kyō built the first purpose-designed fermentation architecture in recorded history. These weren&rsquo;t improvised cellars — they were engineered structures with adjustable ventilation panels, earthen floors that moderated ground temperature, and specific chambers for <em>kan-jikomi</em> (cold-water brewing) and <em>hatsu-zoe</em> (early-stage temperature management). The brewers didn&rsquo;t have thermometers. What they had was three generations of empirical data: which walls faced north, which rooms stayed cool in July, which earthen vessels retained heat overnight. Fermentation temperature control was a craft discipline before it was a science. The Nara-period toji (master brewer) could read a batch by sound — the pitch of CO₂ bubbling through a wooden lid told him whether the koji room was running too warm.</p>