My wife and I are currently doing our kitchen, and have done some shopping specifically in this area. We think we are currently leaning towards a gas cooktop, and then a separate wall oven, for cost and design reasons.
But as we originally planned to do a 36" dual-fuel, and did most of our shopping to date around this, here's a few thoughts/things we learned. Our most important feature was the stove top, so most of these thoughts are about that. We're still not finalized, so I'm also curious what answers others post.
- We talked to multiple sales people from multiple local and nationwide stores. There were sales people that told us that Viking & Wolf were comparable. There were sales people that told us that Viking is overrated, not comparable in quality, and even that Viking was the preferred brand. Essentially, we got conflicting reports to where Viking sits. There was no discrepancy however on the quality of Wolf. They all seemed to agree that at that price point Wolf is top (or very near to) in quality, durability and performance.
- For the stove top Wolf and a few others have a double stacked burner. This means that you can do a extremely low simmer (melt chocolate on a paper plate), on the same burner you do max it out to stir-fry. There was one brand (dacor I believe) where the smaller burner was hidden behind a cast plate. This seems to me to negate the fast response of a gas stove, but that might be just my perception.
- In addition to the double-stacked burners, different brands varied greatly on the versatility of the 5 available burners. 1 15K BTU+ burner, 1 simmer burner, etc... vs. 5 that are generally more versatile. That might not be a problem, you can move pots around as you are cooking, but I'd prefer to minimize the amount of moving I have to do by getting more versatile burners (like the Wolf burners mentioned previously) if I'm at that price point.
What happens to bread when it is done
Yes, there is something particular what happens at a temperature in the mid-90s. Not all details of it are proven, but the major outline is, and the hypotheses about the details are solid enough to make it into textbooks.
Starch is contained in tiny granules, a few micrometers in diameter. When heated in the presence of water, there is a specific temperature at which these granules burst. The molecules of starch come in contact with water and the water molecules get lodged in the nooks and crannies of the much larger starch molecules. This process is called gelating.
You can observe it easily on the macro level. Just cook a bechamel or starch pudding on stovetop, stirring constantly. The liquid will stay rather thin until all will thicken at once, just before you see the first bubbles of boiling. This is when the starch gelates.
The same thing happens in bread too. This is why you want to heat the bread to this temperature. If you don't, you will have raw starch inside, which doesn't taste well.
The exact temperature at which this happens varies a bit with the type of starch. It is not the same for rice and wheat, for example, and I think that it is also a bit different between different wheat cultivars. But the range within this variation occurs is not so wide, all references I have seen move somewhere between 94 and 98 degrees Celsius. So the recipe author just picks a temperature he knows to work for the flour used in the bread, maybe also accounting for some additional heat transfer after taking out of the oven.
Can you use temperature as an indicator for doneness
The theory says yes. My personal experience also says yes. Why did you feel that your bread was too doughy? There are different reasons why this could have happened. You could have measured it wrong (with the probe being too close to the surface, where the temperature is higher). You could have cut it too early. (Bread is always doughy before the first starch retrogradation, which occurs maybe 1 hour after baking). It is also possible that the bread was actually done in the sense of gelled starch, but that the recipe produced a rather moist bread and that you have grown accustomed to dry breads if you normally bake your breads for a very long time, so your brain perceived the unaccustomed texture as "not right". Or it is possible that something went wrong with the leavening, making the bread too dense. Dense bread is always doughy, you cannot bake the moisture out of it.
technical criteria for bread doneness
There are two big chemical changes which happen to bread while baking. The proteins in bread (the gluten) have to harden. Before that, they are soft and pliable. At some temperature, they become rubber-like. The hardened gluten gives the bread structure.
The second change is the starch gelation I explained earlier. When this happens, the liquid part of the dough (dough consists of a liquid phase suspenede in the elastic gluten mesh) thickens. Gelated starch gives bread a fluffy, soft body.
As the starch gelates at much hicher temperatures than proteins denature, bread is taken out of the oven when the starch is done.
The third step is the starch retrogradation. In retrogradation, starch loses the water which it took during gelation. There are three big stages of it, after each the texture changes drastically. The first happens at about an hour after getting out of the oven. This is when the bread is considered done by textbooks. In practice, there are many people (including myself) who like the taste of the moist hot bread just out of the oven, and they consider it done at the previous step. The second happens after about 24 hours; after it, the bread is considered stale. The third step takes several days, and after it, bread is considered inedible, because it becomes hard as wood.
So technically, bread is considered done after it has been baked to gelation temperature and then left alone for 1 hour.
Best Answer
I can't answer in general, but that one's easy. Sudden thermal shock causes strain in a material by unequal expansion, either in the same material by high thermal gradients, or in interfaces between materials with different coefficients of thermal expansion. The strain in this case (two different materials) can be very high. If the material in question is not elastic (e.g. enamel + ceramic; I would think PTFE is different, but I'm not sure), then the bonds between the coating and the metal would be severely strained and it would likely crack and chip.
I can tell you from personal experience that I have actually used this to my advantage:
In the spring, I produce a small quantity of maple syrup by boiling sap in an uncoated stainless steel pan. On rare occasions, accompanied by the release of many expletives, I have let the syrup boil down too far, at which point it burns and seems to coat the bottom of the pan with a thin but hard and very resilient layer of carbon black. The trick to removing this stuff is to get some kind of stress crack started, e.g. by scrubbing w/ steel wool or a copper pad, and then what I do is I put the pan on the stove for a while to let it heat up hot (but not red hot), and then bring it over to the sink and spray cold water on the inside pan bottom where the carbon black has stuck to. After a few times, the carbon black will start to flake off and then it becomes easier to remove by a combination of abrasion and thermal shock. (The two pans I've done this on have been fine; both are stainless steel with a thick (>8mm) bottom, and I've put them through at least 30 or 40 thermal cycles of this type.)
edit re: general topic:
Wikipedia says this:
Higher thermal conductivity means it's more difficult to get a large thermal gradient across the material (less prone to shock); higher thermal expansion means more strain (more prone to shock), and higher Young's modulus means more stress for a given strain (more prone to shock).
So theoretically you could compare the different materials. (exercise for the reader ;) Most likely copper would be more resilient than the other metals, because of its higher thermal conductivity and higher ductility.
Thermal conductivity k: Copper = 401, Aluminum alloys = 120-180, stainless steel = 12-45 (units = W/m*K)
σT: no idea:
Coefficient of thermal expansion α: Copper = 17, Aluminum = 23, iron = 11.1, stainless steel = 17.3 (units = 10−6/°C)
Young's modulus E: Copper = 117, Aluminum = 69, iron/steel = around 200 (units = GPa)
Poisson's ratio ν: Copper/stainless steel/aluminum are all around 0.3-0.33, cast iron = 0.21-0.26
So stainless steel is worse than aluminum or copper (much lower thermal conductivity, higher Young's modulus).