Vibram IPA

Three temperature profiles that seem to be popular among homebrewers are just off boil range 190–212 °F (88–100 °C), the sub-isomerization range 160–170 °F (71–77 °C), and a tepid hop stand range 140–150 °F (60–66 °C). The 190–212 °F (88–100 °C) range will allow essential oils with higher flashpoints an easier time to solubulize into the wort and also will allow some alpha acid isomerization to occur with the best estimates of between 5–15% utilization. Some homebrewers will keep their kettle burner on low to keep the temperature of the wort elevated above 200 °F (93 °C) during their extended hop stands which would better emulate the conditions in commercial whirlpools. A hop stand in the 160–170 °F (71–77 °C) range will basically shut down the alpha acid isomerization reaction and the lower temperatures will reduce the vaporization of the essential oils. Homebrewers can use their wort chillers to bring the wort down to this range before adding the knockout hops or they can add a second dose of knockout hops. The 140–150 °F (60–66 °C) range will once again reduce vaporization of the low flashpoint oils, but may take longer to get the same amount of essential oils extracted.