Completion of Mixing Series

I completed my series of batches with the dough mixed for different lengths of time. I reported the procedure in my post of February 15, 2010. I have attached a photo. The top row shows cookies mixed for 2, 3, 4, and 5 minutes and then baked on my non-stick Wilton EverGlide pans. The bottom row shows the same cookies baked on my Williams-Sonoma Goldtouch Commercial Quality Cookie Sheet.

I talked about the 2- and 3-minute batches on the 15th and the 17th. The 4- and 5-minute batches continue to bear out the necessity of mixing the dough well enough in order to avoid pitting in the dough on the nonstick Wilton pan - all the batches mixed for at least three minutes had no pitting during baking.

The dough from 2, 3, and 4-minute mixing felt progressively drier at the end of the mixing period. The 4-minute dough had a bit of a hard time holding together as I formed rolls of dough - it did not adhere to itself very well, and wanted to break into chunks. The cookies it made were OK, but not as good as the 3-minute cookies because they were harder, as I expected. I also expected a continuation of that pattern in the 5-minute dough, but I was quite surprised to find that the 5-minute dough felt much like the 3-minute dough. I think that's a fairly important observation. The dough mixed for five minutes was coincidentally somewhat warmer at the end of the creaming period. Importantly, an extra minute of mixing raised the temperature even further. I didn't measure the temperature of the dough after I was finished mixing the flour in, but I have a feeling it was a fair amount warmer than the 4-minute dough. If that's the case, the higher temperature probably helped the dough be a little more coherent as I formed the rolls.

What really did surprise me was that the 5-minute dough made softer cookies than the 4-minute dough. During the 4-minute mixing, it looked like the dough was forming some gluten strands, because as it was pulled away from the side of the bowl strands of dough would stretch in the direction of the pull and be left on the side of the bowl. I didn't observe that at all while mixing the 5-minute dough. That seems a bit of a mystery to me, because the only difference was that the temperature was a degree or two higher in the 5-minute dough. What difference would that make? Unless such a small difference in temperature actually makes a difference in gluten formation, I can't explain it, because everything else was the same for the 4- and 5-minute doughs. In any case, the 4-minute dough seemed to show some gluten strands and the cookies were harder, while the 5-minute dough did not show the same strand effect, and the cookies were not hard.

Even though the 5-minute dough was less hard, like the 3-minute dough, the cookies weren't the same. The cookies mixed for 5 minutes tasted less sweet. That doesn't make that much sense to me, but that's how it was. The way I can perhaps explain it is to say that the flour was more spread out in the cookie, and so my tongue came into contact with the flour more easily, which "diluted" the sweetness of the cookie.

Take a look at the cookies in the top row of the photo, the ones baked on the Wilton pan. Notice how much larger the 2-minute and 5-minute cookies are than the ones from 3 and 4-minute mixing. That's not just by chance. All the cookies baked with 3 or 4 minutes of mixing on the Wilton pan were smaller and tighter than any I'd seen baked on the Wilton pan previously. Normally the high heat from the Wilton pan causes the cookies to spread quite a lot. Apparently the extra mixing in the 3 and 4-minute cookies "rearranged" the butter so that the flour did not spread as easily. The 5-minute cookies spread like the 2-minute cookies, though. The doesn't make a lot of sense, but that dough did seem to have gotten warmer during the creaming and mixing, and perhaps somehow the temperature reached during that period not only interfered with gluten formation, but prevented the butter from dispersing as much as it did in the 3 and 4-minute cookies.

I ran across some interesting information on the allrecipes.com page on cookies: "Over-mixing can incorporate too much air into the dough, resulting in flat, overly spread-out cookies." Could that explain the extra spreading of the 5-minute cookies? I'm thinking maybe not. I know that the creaming step is where air gets incorporated into the cookies, and that Web page mentions creaming under the same "Mixing" header. I think that sentence most likely refers to creaming for too long, rather than the portion of mixing after flour is added. But I could be wrong!

My tentative conclusion from these experiments is that when I add 4 cups of flour to 2 cups of creamed butter and sugar, after adding the first two cups of flour and mixing for 20 seconds and then adding the rest, it is sufficient to mix the dough for an extra 3 minutes.