Using the exact same wort composition but with a 60 minute boil, this example in "Principles of Brewing Science: A Study of Serious Brewing Issues" computes only 92 µg/L of DMS, mostly because a lot more of the SMM is converted to DMS during boiling, which is then volatilized during the boiling, and leaving less SMM to convert to DMS during cooling. Even with the higher SMM during cooling in our heat pasteurized wort example, that hardly seems fair considering that the half-life of SMM is ~300 minutes at the pasteurization temperature of 82°C.
===Numerical Modeling Using Updated Volatilization EquationsDMS Volatility Data===
If instead we just use Rather than using Fix's average half-life approach, numerical modeling divides the heating, boiling and cooling times into very small time steps (for the work below, a time step of 0.6 seconds was used), during which the temperature is approximated to be constant. The computer program calculates the first equation that predicted how much amount of SMM is decomposed into converted to DMS during the heat pasteurization timestep, we get a much lower value the amount of SMM that is decomposed into DMS. This approach takes into consideration volatilized during the time step, then plots the [[Dimethyl_Sulfide#Mashing_and_Boiling|half-life of total DMS and SMM]] in the wort at any given temperature rather than taking the average end of the starting time step. Finally, the program calculates a new temperature and ending (which depends on whether the wort is heating up, being held at a constant temperature during , or cooling). [https://www.facebook.com/mark.hammond.1253 Mark Hammond] from MTF used a computer The program to model then loops through all the conversion of SMM to DMS based on SMM half-life calculations at any given this new temperature, calculating all the same quantities for the next time step. The new equations from [http://onlinelibrary.wiley.com/doi/10.1002/jib.301/full "Scheuren, Baldus, Methner and Dillenburge (2016): Evaporation behaviour of DMS in an aqueous solution at infinite dilution – a review"] were used to determine the evaporation of DMS during the cooling time (this assumes an open cooling system; closed cooling systems will retain this DMS). Hammond assumed a linear heating rate, and used Newton's Law of Cooling for the cooling ratewith constants based on empirical data taken from his own homebrewing equipment. Evaporation rates were likewise modeled using thermodynamic equations and empirical data from Hammond's equipment. By observing these estimations, it can be seen that no-boil or "raw ale", and wort boiled for short durations, Hammond predicts less DMS than what is predicted using the traditional model.
For the DMS amounts in the following graphs, Hammond calculated the mass of DMS to be 62/164 of a gram of DMS for every gram of SMM decomposed. Since we get one molecule of DMS (62 g/mole) from each molecules of SMM (164 g/mole), we don't get one for one mass of DMS for SMM. Keep that in mind when comparing the decline in the SMM concentration graph to the DMS concentration graph <ref name="hammond">Private correspondence between Mark Hammond and Dan Pixley. 03/15/2016 - 03/23/2016.</ref>.