Monday, December 11, 2006
Taking the new kettle for a spin
I thought that using the new kettle for the two batches yesterday was a little premature as I was unsure of whether the stove could actually bring 30 liters to a boil. Instead I used my old 20 liter and 13 liter pots to boil the 28-30 liters of wort retrieved from the mash. That has worked fine on this stove and it usually takes about 15 minutes to get the big pot to a boil from mashout temperature, and about the same time to get the little one to a boil, but that one is put on the stove 15 minutes later as it contains the output of the second [batch] sparge. As I boil the beer for a total of 90 minutes this works just fine as I can have both pots ready at a full boil for the first hop infusion at 60 minutes.
In order to find out whether the stove, on which the biggest element is 2000 watts (or 1800 watts for all I know), would be good enough for the job. I started out by filling the kettle with 30 liters of 12 degrees C tap water. This took exactly 2 hours to bring to a boil, at 100C, with the lid covering the the kettle.
Sugar solutions, like wort, have a slightly higher boiling temperature, so it will in theory require a bit more energy to reach a rolling boil. The stove was able to maintain a decent rolling boil even after I removed the lid. That's pretty good, but the time it took to reach a boil was substantial.
This all means that my stove is able to heat 30 liters of water at a rate of 0.73C per minute. In theory that means that it should be able to raise the wort from a mashout temperature of 76C to 100C in 17.6 minutes -- provided that there is no temperature loss between mashout and starting to heat the kettle. In real life I would expect something like 25 minutes.
So, given this, I think I'll give the brew kettle a try for my next brew, just to see how it behaves with actual wort and in a real setting. But, there is no doubt I will need a little more power to cut down on the time and make the boil more vigorous. One alternative might be to insulate the kettle.