direct heat vs. boiler

[murmsk]

How big a system can you use direct heat on before having to go to a boiler and calandria?

thanks steve

[brewmaster 2011]

Boiler with steam jacketed mash/lauter and jacketed kettle/whirlpool. I have never used a calandria so I can't give an opinion on it. I have used direct fire and steam jacket and have to say steam is easier to control and will not cause kettle scorching like direct fire.

[murmsk]

agreed.... however there is quite a cost difference. We are in the planning stages of starting a brewery on a very small scale and I am trying to get an idea of at what size we need to begin to think of other heating sources other than direct fire. When does scorching become a problem? I assume a 800,000 btu burner will scorch the hell outta stuff.... 300,000? 250,000.

what is the general conciseness?

steve

[brewfun]

Scorching isn't about the btu's. It's about the heat density. Properly spaced gas jets will effectively transfer heat to the kettle without scorching. A professionally built system will have taken that into account.

However, in side by side comparisons of recipes, I do notice a shade or two deeper color and melanoidin richness with direct fire. Not usually enough to be a huge concern.

[dick murton]

I have been led to believe that traditional wort kettles up to about 300 UK brls (490 hl, or about 420 US brls) can be successfully direct fired, though of course, it involves a fair bit of work when fired by coal or wood!! Certainly some of the 165 uk brl (230 US brl) copper kettles at one of the breweries I worked at were originally coal fired - there were still the ashes in the hearth areas when we demolished the place.