![]() Kettle Geometry larger kettles are more efficient.Boils longer than 90 mins iso-alpha acids start to break down to unidentified and undesirable components.The relationship between time and Utilisation is non-linear.The limited solubility of Alpha acid and Iso alpha acid in wort.Hop pallets are ~10-15% more efficient than hop cones. Hop form – whole, fresh, pallets, extracts etc. ![]() However, with any calculation, many variables affect Utilisation. Since Tinseths research was compiled, there has been some modifications and improvements have been made when calculating flameout, whirlpool and low-temperature hop additions. The Glen Tinseth equation for predicting IBU is the most used calculation for calculating hop utilisation during the boil. It also includes an option to apply alpha-acid solubility limit correction.įor more information about the mIBU technique see the full article here. It does this by modelling your post-boil temperature throughout hop stand (if applicable) and cooling stages, and then calculates the corresponding IBU contributions based on those temperatures. Our recommended method (and default going forward in the recipe creator) is the mIBU method, developed by Paul-John Hosom. It is based on the Tinseth equation but includes many optimisations such as a way to model post-boil bitterness contributions by taking into account additional equipment/process parameters. The Grainfather Brewing community tools offers a choice of the following bitterness methods: With an average yeast flocculation and no filtration. Utilisation rate as a function of boil time for wort of SG 1.050 boiled at sea level using low hopping rate with fresh leaf hops without a hop bag. Tinseth, Rager, Garetz, Mosher, Noonan or Daniels all have equations that can be used to calculate IBUs when brewers are developing recipes and the key differences being how each of them approached Hop Utilisation, as seen in the figure below.įigure 1: Utilisation Rate as a Function of Boil Time and Simple beer IBU (Michael L. Or many small breweries rely on the estimates as they don’t have access to the laboratories or don’t see the value in testing. Therefore, brewers, today benefit from the IBU, as a tool when formulating recipes and maintaining bitterness levels in regularly brewed beers while recognising that the IBU does not entirely reflect the quality of the bitterness or the overall perception of bitterness. Today high-pressure liquid chromatography is used to measure iso-alpha acids, but this is unique to the beer brewed under their specific conditions. Still, due to cold storage, high alpha hops with low beta acids and the use of hop products less susceptible to oxidation means the factor used in the original calculation may not be a true representative of the bitterness of beers today (Peacock, 2007). Since this method was developed using beers in the 1960s where the hops they were using in the brewing process were very oxidised compared to those we get today, which for the beers of the 1960s worked well. There are, however, several shortcomings of the IBU. The IBU is a measure of the Isomerised alpha acids and non-isomerised hop material in a finished beer when analysing by UV-Vis spectroscopy then multiplied by a correction factor to get the expressed overall bitterness in beers from the 1960s (Hieronymus, 2012). IBU or International Bitterness Unit was created to help brewers make beer with a consistent level of bitterness. If you'd like to have a listen to a bit of an overview on this topic, our experts are featured on this podcast explaining more about IBU in relation to hop usage. ![]() This article goes through the resources and information Grainfather uses to calculate IBU’s on the recipe creator.
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