I love your explanations. :)
On Wed, 16 Feb 2005 21:39:22 -0500, Adam Churvis <[EMAIL PROTECTED]> wrote: > William, > > A really *good* convection oven makes all the difference in the world. Just > make sure to keep the insides spotlessly clean, as the dark spots absorb > more radiation than you'd think. > > There are three general ways to heat: by conduction (with contact), by > convection (with directed flow), and by radiation. All conventional > (non-microwave or other exotic) ovens are radiation ovens by default; a > "convection" oven just adds convection to the mix. > > To give you an idea of why convection is so good for baking and roasting, > let's take the opposite -- cooling -- as an everyday example. When you're > sweating and you come into a cool room and sit still, you cool a little bit > because the liquid coolant of your sweat is evaporating slowly into the > surrounding air, and you get cooling by evaporation. Now if you run a fan > over your skin you feel significantly cooler because you're achieving > cooling by convection, and here's why: if you shrunk down to microscopic > size and peered at a droplet of sweat evaporating, you'd see a > supersaturated layer of moist air just above the droplet, and that > supersaturated layer acts as a kind of barrier to more moisture saturating > the surrounding air (and thereby cooling you). A vector of air continually > strips off that supersaturated air layer and allows the droplets to saturate > the surrounding air faster, hence the drop in skin tempurature. > > Now reverse this principle using heating instead. Your loaf is heating by > radiation, and the moisture is leaving through the top of the loaf, where a > supersaturated layer of moist air slowly burns dry while the rest of the > oven fills with even more moisture from the loaf, which absorbs some of the > oven's heat and seeps out like a tiny steam leak (one reason why your > kitchen gets so hot with a non-convection oven). Now stream a vector of hot > air over that moise loaf of bread and you'll not only continually strip off > that layer of moisture, you'll exhaust it from the oven in a controlled > fashion so there's less steam to absorb radiant heat and leak out of your > oven. This is another reason why you almost always get a better finish on > baked goods and roasts, both of which are optimally "dry heat" cooking > techniques that are hindered by moisture. > > I know this was long-winded, but hopefully it answers the "why" of it all, > and hopefully this helps you. > > Respectfully, > > Adam Phillip Churvis ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| All-in-one: antivirus, antispam, firewall for your PC and PDA. Buy Trend Micro PC-cillin Internet Security http://www.houseoffusion.com/banners/view.cfm?bannerid=60 Message: http://www.houseoffusion.com/lists.cfm/link=i:5:147459 Archives: http://www.houseoffusion.com/cf_lists/threads.cfm/5 Subscription: http://www.houseoffusion.com/lists.cfm/link=s:5 Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.5 Donations & Support: http://www.houseoffusion.com/tiny.cfm/54
