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I finished my cookie pan calibration - for now. I'll report the final results right up front: (and by the way, I found my HTML book but apparently if I put a table in a post it doesn't display correctly)
Baking Sheet Calibration Times
15 x 14 aluminum insulated
density = 1.42 g/sq.in.
12 minutes
15 x 14 GoldtouchTM insulated
density = 2.19 g/sq.in.
13 minutes
13 x 9 Good Cook traditional finish
density = 2.21 g/sq.in.
11 minutes
13 x 12 Good Cook/Oneida slide-off
density = 2.62 g/sq.in.
7.5 minutes
15 x 14 Good Cook/Oneida slide-off
density = 3.20g/sq.in.
7 minutes
15.25 x 10.25 Wilton EverglideR
density = 4.36 g/sq.in.
7 minutes
16 x 14 Williams-Sonoma Commercial Quality Cookie Sheet
density = 4.80 g/sq.in.
11.5 minutes
15 x 12 Chicago Metallic jelly roll non-stick
density = 5.03 g/sq.in.
6.5 minutes
In my post on January 10, 2010, I described how I calibrated my baking sheets - bake the same cookie recipe on each sheet and, for each, find the time that created a cookie that was just beginning to brown around the edges. Subsequently I looked at the bottoms of the "standard" baked cookies from each pan, and saw that they were baked to entirely different degrees, and so my initial method had a flaw. Finally I noticed that after a certain period of time in the oven, the cookies developed a crisp break. It seems to me that the crispness defines a degree of doneness which is more reliable than looking at either the top or the bottom of the cookies. There is no appearance that can be found identically on all the pans, unless you count the plain white of unbaked cookies, which isn't helpful. The point of crispness appears identically on every pan, though, and is directly related to a quality of the whole cookie rather than only the surface. I decided to perform the final baking sheet calibration by determining how many minutes needed to pass before the point of crispness was reached.
The times I determined by this method were mostly similar to the original method, but they were not identical. Most notably, the times on insulated pans were a fair amount longer.
During this calibration I baked the cookies with the baking sheets "full," unlike in my initial tests. Definition of "full": cookies about 2.75" apart center-to-center. The cookies had widths about 1.25" across. I followed the same procedure as before, except that I quadrupled the recipe from Step 1 of the calibration, using 2 cups of butter, 2 cups sugar, etc. I divided the quadrupled dough into four equal parts and refrigerated rolled in waxed paper, with rolls about 11.5" long (just less than the width of the waxed paper). After I took the sliced cookies from the refrigerator and placed them on the baking sheets, I waited five to six minutes before placing the baking sheets in the oven. In my initial calibrations I wasn't timing the delay, but since this was the "real thing" I wanted to be sure to do everything the same for each batch. It's probably important to emphasize that this experiment was performed entirely without parchment paper or other lining on the baking sheets. At some point I'll look at exactly how those affect baking times on different pans, but these results are for bare unlined baking sheets.
I bought and calibrated two additional baking sheets. To explain the first additional purchase, in a couple of stores I saw pans sold as "jelly roll pans," but they said they were for cookies, too. (Who the heck makes jelly rolls these days? I didn't know anybody did. I haven't had a bite of one in years - sounds great!!!) They look pretty much like cookie pans, but the sides are about 1 inch high, higher than sides on cookie pans. Bed, Bath & Beyond sold such a jelly roll pan manufactured by Chicago Metallic, which I purchased to do some testing with. I have read and been told that it's better to have pans with low or no sides in order to promote even flow of air over the tops, and I wanted to see how these jelly roll pans would work, with their higher sides. The jelly roll pan is very heavy, relatively speaking - it's definitely my heaviest pan - and non-stick, with a dark color similar to the Wilton pan although the finish has little reflectivity, probably even less than the slide-off pans. For a pan of such simple construction it is quite expensive - it cost me about $20, and so I only bought one. It's not like I needed more baking sheets!
Bed, Bath and Beyond also sells jelly roll pans manufactured by Chicago Metallic in a set of three of different sizes for the same price. The size I bought, 15 x 12, is a good size, but I was surprised to see that it is not one of the sizes in the set of three. I don't know if the qualities of the metal in the pans in the set of three is the same as the metal in the pan I bought. If it's the same, I'd have been better off buying the set of three for the same price! But I think I picked that set up and they didn't seem heavy enough to be the same. I wouldn't stake my life on them being different, though. For some reason I don't find my pan listed on their Web site.
The second pan was from Williams-Sonoma. After I calibrated all the others, it looked like the calibration times were pretty much in inverse relationship to the density of the pans. However, at that point it also happened that the three pans with longest calibration times were all pans with traditional (i.e. not non-stick) finish. I wanted to know whether calibration times were really dependent on the density of the pans, or was it the finish type, so I bought and calibrated a heavy baking sheet with traditional finish. Williams-Sonoma mostly has non-stick baking sheets, as do most stores, and the first time I'd visited the store looking at baking sheets they were out of their regular baking sheet with traditional finish. I bought their insulated pan with traditional finish before, but that's a horse of a different color, so to speak. Now the pan was in stock at Williams-Sonoma, and I came home with my pocket $17.94 lighter, including tax. (I see their Web site advertises a set of two for $30 at today's price, plus tax & shipping.)
The Williams-Sonoma pan is labeled "Commercial Quality Cookie Sheet, 16 x 14, a Williams-Sonoma Exclusive". It is actually manufactured by Chicago Metallic. It's quite heavy like the other Chicago Metallic pan, but this one has no vertical edges. Two opposite edges are bent upwards at an angle to provide a grip. There is a very slight rise along the very edge on the other two sides, I suppose to keep spreading cookies from dripping off the edge of the pan if they are placed too close.
The table above shows not only the calibration times, but also the density of the metal in grams per square inch. (Mixed metric and English system measurements! Excellent!) I listed the pans in order of increasing density, and I think it's extremely interesting that the calibration times tend to decrease almost precisely in the order of increasing density. This is probably not a coincidence, but the calibration time of the Williams-Sonoma Commercial Quality Baking Sheet shows that the calibration times are far more closely related to the finish. Every baking sheet with traditional shiny, metallic-looking finish, whether heavy or light, has a calibration time of ten minutes or longer. Every baking sheet with non-stick finish has a calibration time of 7.5 minutes or shorter. However, I think two pans with the same finish will generally have calibration times in inverse order to their density. (But not always! I think it also has to do with how mirror-like the finish is.)
I need to mention that for the two insulated pans, the density was calculated including only the weight of one of the two layers, since the bottom layer of the pans doesn't actually touch the cookies.
If someone wants to calculate where their own pans fall in this list by density, they can calculate the density of their own pans by first getting its weight in grams and dimensions in inches. The formula I used for the density numbers above is:
density = weight in grams / (width in inches x height in inches)
One thing about these times really jumps out at me. Cookie recipe baking times usually give a range of a couple of minutes, for example "bake 9-11 minutes". The advice is to check the cookies at the earliest time the first time you make them, and if they aren't done yet they should be done by the end of the time range. The range of calibration times is from 6.5 all the way up to 13 minutes. That indicates that recipe baking ranges really need to span 6 or 7 degrees in all cookie recipes, if the various different sorts of baking pans are to be accommodated. It also makes me realize that recommended baking times in different cookbooks can occasionally be based on times measured with some specific pan, and be vastly off for the pans most other people have. I've read that with insulated pans you need to add a couple of extra minutes. This data shows that compared to typical non-stick pans, insulated pans probably take an extra five or six minutes. And in general, non-stick pans are about three minutes quicker than pans with traditional finish.
I am not entirely comfortable with these calibration times, because I had to make many batches of dough in order to have enough cookies for full sheets with all these pans and to do the full calibration regimen with two new pans. Even though I tried to do the same thing with each batch of dough, there were definitely small differences in the procedure that I know for sure affected baking times, and so calibration between pans is thrown off. Within a single batch baking times were very reproducible, but it's much more difficult between batches. (That's what this blog is about, making great cookies reproducibly, and I still have a ways to go!) The only practical way to do a reliable calibration is to make a single batch of dough, enough for every pan and more. With two pans, it's easy to do. With eight, not so easy! Now that I have a really good handle on what the times should be, I may go back and make that monster batch of cookie dough sometime in a few weeks, but to be honest, right now I've had all the cook pan calibrating I can stomach. :-) I am reasonably confident these times are within about a minute of where they should be, though.
I'll have some things to say about the appearances of the equally-baked cookies on different pans shortly. The photo I'm attaching shows a few of the cookies scattered about my kitchen. It doesn't show the several dozen cookies stacked on the washer, dryer, and stovetop.
Baking Sheet Calibration Times
15 x 14 aluminum insulated
density = 1.42 g/sq.in.
12 minutes
15 x 14 GoldtouchTM insulated
density = 2.19 g/sq.in.
13 minutes
13 x 9 Good Cook traditional finish
density = 2.21 g/sq.in.
11 minutes
13 x 12 Good Cook/Oneida slide-off
density = 2.62 g/sq.in.
7.5 minutes
15 x 14 Good Cook/Oneida slide-off
density = 3.20g/sq.in.
7 minutes
15.25 x 10.25 Wilton EverglideR
density = 4.36 g/sq.in.
7 minutes
16 x 14 Williams-Sonoma Commercial Quality Cookie Sheet
density = 4.80 g/sq.in.
11.5 minutes
15 x 12 Chicago Metallic jelly roll non-stick
density = 5.03 g/sq.in.
6.5 minutes
In my post on January 10, 2010, I described how I calibrated my baking sheets - bake the same cookie recipe on each sheet and, for each, find the time that created a cookie that was just beginning to brown around the edges. Subsequently I looked at the bottoms of the "standard" baked cookies from each pan, and saw that they were baked to entirely different degrees, and so my initial method had a flaw. Finally I noticed that after a certain period of time in the oven, the cookies developed a crisp break. It seems to me that the crispness defines a degree of doneness which is more reliable than looking at either the top or the bottom of the cookies. There is no appearance that can be found identically on all the pans, unless you count the plain white of unbaked cookies, which isn't helpful. The point of crispness appears identically on every pan, though, and is directly related to a quality of the whole cookie rather than only the surface. I decided to perform the final baking sheet calibration by determining how many minutes needed to pass before the point of crispness was reached.
The times I determined by this method were mostly similar to the original method, but they were not identical. Most notably, the times on insulated pans were a fair amount longer.
During this calibration I baked the cookies with the baking sheets "full," unlike in my initial tests. Definition of "full": cookies about 2.75" apart center-to-center. The cookies had widths about 1.25" across. I followed the same procedure as before, except that I quadrupled the recipe from Step 1 of the calibration, using 2 cups of butter, 2 cups sugar, etc. I divided the quadrupled dough into four equal parts and refrigerated rolled in waxed paper, with rolls about 11.5" long (just less than the width of the waxed paper). After I took the sliced cookies from the refrigerator and placed them on the baking sheets, I waited five to six minutes before placing the baking sheets in the oven. In my initial calibrations I wasn't timing the delay, but since this was the "real thing" I wanted to be sure to do everything the same for each batch. It's probably important to emphasize that this experiment was performed entirely without parchment paper or other lining on the baking sheets. At some point I'll look at exactly how those affect baking times on different pans, but these results are for bare unlined baking sheets.
I bought and calibrated two additional baking sheets. To explain the first additional purchase, in a couple of stores I saw pans sold as "jelly roll pans," but they said they were for cookies, too. (Who the heck makes jelly rolls these days? I didn't know anybody did. I haven't had a bite of one in years - sounds great!!!) They look pretty much like cookie pans, but the sides are about 1 inch high, higher than sides on cookie pans. Bed, Bath & Beyond sold such a jelly roll pan manufactured by Chicago Metallic, which I purchased to do some testing with. I have read and been told that it's better to have pans with low or no sides in order to promote even flow of air over the tops, and I wanted to see how these jelly roll pans would work, with their higher sides. The jelly roll pan is very heavy, relatively speaking - it's definitely my heaviest pan - and non-stick, with a dark color similar to the Wilton pan although the finish has little reflectivity, probably even less than the slide-off pans. For a pan of such simple construction it is quite expensive - it cost me about $20, and so I only bought one. It's not like I needed more baking sheets!
Bed, Bath and Beyond also sells jelly roll pans manufactured by Chicago Metallic in a set of three of different sizes for the same price. The size I bought, 15 x 12, is a good size, but I was surprised to see that it is not one of the sizes in the set of three. I don't know if the qualities of the metal in the pans in the set of three is the same as the metal in the pan I bought. If it's the same, I'd have been better off buying the set of three for the same price! But I think I picked that set up and they didn't seem heavy enough to be the same. I wouldn't stake my life on them being different, though. For some reason I don't find my pan listed on their Web site.
The second pan was from Williams-Sonoma. After I calibrated all the others, it looked like the calibration times were pretty much in inverse relationship to the density of the pans. However, at that point it also happened that the three pans with longest calibration times were all pans with traditional (i.e. not non-stick) finish. I wanted to know whether calibration times were really dependent on the density of the pans, or was it the finish type, so I bought and calibrated a heavy baking sheet with traditional finish. Williams-Sonoma mostly has non-stick baking sheets, as do most stores, and the first time I'd visited the store looking at baking sheets they were out of their regular baking sheet with traditional finish. I bought their insulated pan with traditional finish before, but that's a horse of a different color, so to speak. Now the pan was in stock at Williams-Sonoma, and I came home with my pocket $17.94 lighter, including tax. (I see their Web site advertises a set of two for $30 at today's price, plus tax & shipping.)
The Williams-Sonoma pan is labeled "Commercial Quality Cookie Sheet, 16 x 14, a Williams-Sonoma Exclusive". It is actually manufactured by Chicago Metallic. It's quite heavy like the other Chicago Metallic pan, but this one has no vertical edges. Two opposite edges are bent upwards at an angle to provide a grip. There is a very slight rise along the very edge on the other two sides, I suppose to keep spreading cookies from dripping off the edge of the pan if they are placed too close.
The table above shows not only the calibration times, but also the density of the metal in grams per square inch. (Mixed metric and English system measurements! Excellent!) I listed the pans in order of increasing density, and I think it's extremely interesting that the calibration times tend to decrease almost precisely in the order of increasing density. This is probably not a coincidence, but the calibration time of the Williams-Sonoma Commercial Quality Baking Sheet shows that the calibration times are far more closely related to the finish. Every baking sheet with traditional shiny, metallic-looking finish, whether heavy or light, has a calibration time of ten minutes or longer. Every baking sheet with non-stick finish has a calibration time of 7.5 minutes or shorter. However, I think two pans with the same finish will generally have calibration times in inverse order to their density. (But not always! I think it also has to do with how mirror-like the finish is.)
I need to mention that for the two insulated pans, the density was calculated including only the weight of one of the two layers, since the bottom layer of the pans doesn't actually touch the cookies.
If someone wants to calculate where their own pans fall in this list by density, they can calculate the density of their own pans by first getting its weight in grams and dimensions in inches. The formula I used for the density numbers above is:
density = weight in grams / (width in inches x height in inches)
One thing about these times really jumps out at me. Cookie recipe baking times usually give a range of a couple of minutes, for example "bake 9-11 minutes". The advice is to check the cookies at the earliest time the first time you make them, and if they aren't done yet they should be done by the end of the time range. The range of calibration times is from 6.5 all the way up to 13 minutes. That indicates that recipe baking ranges really need to span 6 or 7 degrees in all cookie recipes, if the various different sorts of baking pans are to be accommodated. It also makes me realize that recommended baking times in different cookbooks can occasionally be based on times measured with some specific pan, and be vastly off for the pans most other people have. I've read that with insulated pans you need to add a couple of extra minutes. This data shows that compared to typical non-stick pans, insulated pans probably take an extra five or six minutes. And in general, non-stick pans are about three minutes quicker than pans with traditional finish.
I am not entirely comfortable with these calibration times, because I had to make many batches of dough in order to have enough cookies for full sheets with all these pans and to do the full calibration regimen with two new pans. Even though I tried to do the same thing with each batch of dough, there were definitely small differences in the procedure that I know for sure affected baking times, and so calibration between pans is thrown off. Within a single batch baking times were very reproducible, but it's much more difficult between batches. (That's what this blog is about, making great cookies reproducibly, and I still have a ways to go!) The only practical way to do a reliable calibration is to make a single batch of dough, enough for every pan and more. With two pans, it's easy to do. With eight, not so easy! Now that I have a really good handle on what the times should be, I may go back and make that monster batch of cookie dough sometime in a few weeks, but to be honest, right now I've had all the cook pan calibrating I can stomach. :-) I am reasonably confident these times are within about a minute of where they should be, though.
I'll have some things to say about the appearances of the equally-baked cookies on different pans shortly. The photo I'm attaching shows a few of the cookies scattered about my kitchen. It doesn't show the several dozen cookies stacked on the washer, dryer, and stovetop.
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