Brewer’s Cache

Your boil time and the rate at which you cool the wort post-boil will certainly affect the outcome of your beer. Whenever your wort is above 150 degrees F, an unpleasant-tasting chemical compound called DMS is generated. DMS tastes like cooked vegetables–corn in particular. But as long as the wort is being boiled in an uncoverd pot, the DMS that is generated is carried away with the steam. When the wort temperature falls below the boiling point, DMS is still being generated but is no longer being carried away and DMS levels in your wort will begin to rise.

If your brewing equipment is limited to the starter set that you purchased, the best method that you have available to cool you wort is to set your boil vessel into an ice bath. In an ice bath, it could take as long as 15 to 20 minutes to get the wort temperature below this 150 F threshold and DMS will accumulate during this period. If you are in this group, like I am, what are your options? Boil longer. By extending your boil to 90-120 minutes, almost all of the DMS that will be generated during the boil will have been generated and driven off; very little will continue to be generated when during the cooling stage.

This problem can be circumvented through proper cooling techniques. Using an immersion chiller will dramatically decrease the time the wort spends in the “DMS zone.”

As a rule of thumb, if you use an ice bath, you must boil you wort at least 90 minutes to avoid DMS off-flavors. If you use an immersion chiller, you are free to decrease your boil duration to 60 minutes. It is important to note that longer boils will improve hop utilization and certainly cause a darkening effect on your beer. If you don’t time your hop additions correctly, you could end up with quite a bitter beer.

Happy brewing!

Popularity: 1% [?]