What purpose does kneading/mixing serve?
First post from a long-time lurker -- apologies for the length. I'm a regular baker, and I've baked some bread most weeks for the past decade or so. I also dabble and experiment a lot.
Recently I've started wondering about why we actually knead/mix beyond just combining ingredients. A friend who was asking me about the value of folding got me onto this question -- I started researching folding and ended up wondering what kneading/mixing actually does that can't be done as well (or better) by additional folding where necessary. I'm not talking necessarily about the "no-knead" methods that have been in vogue for the past few years, which generally depend on a very long fermentation to develop gluten, though perhaps they also bear on this question. I assume that for "standard" method breads, the initial knead/mix must be in part replaced by additional folding and perhaps modifications during shaping.
When I first started baking, I generally used the oft-touted "windowpane test" to know when I'd achieved adequate mixing/kneading. A few years back I read things which have shown me that that isn't necessarily the best criteria. Hamelman is one source that gives some detail:
Appropriate development does not necessarily mean full gluten development.... If our only goal is dough volume, a lot of yeast and maximum gluten development in the mixer is the method of choice. Maximum volume is one thing, however, and maximum flavor another, and a mixing technique that favors utmost volume will also compromise flavor. [p. 8, emphasis in original]
Hamelman goes on to point out that mixing incorporates oxygen, which is important for gluten development, but he points out that too much oxygen ruins flavor by destroying carotenoids. Elsewhere, he also notes that the oxygen incorporated during mixing is consumed within minutes by the yeast (p. 13); I'm not sure whether that has any impact on the ongoing gluten development, though.
He then contrasts heavy mixing with very light mixing, describing the latter thus:
[I]magine that the dough is mixed very slowly, on low speed only.... Gluten development is at a minimum, as is the oxidation of the dough. Bulk fermentation lasts for many hours, punctuated by a number of folds, and the dough slowly reaches maturity. The carotenoids are not oxidized out of the dough, and the bread flavor is superb. Loaf volume, however, is comparatively small, because of the relative lack of physical dough development. [pp. 8-9]
In the end, Hamelman argues for a middle course, which develops dough strength but doesn't destroy flavor. Most books seem to agree, and many even say that, short of overmixing in a professional mixer, you're unlikely to overdevelop the dough in an initial mix. But in the description I've quoted here, it seems that the effects of little kneading are mixed (pardon the pun) -- the dough requires more tending (folding, and a longer fermentation), but the flavor is greater.
Yet I wonder about his conclusion that the loaf volume is necessarily "comparatively small." In my experience (which is not that of a professional baker), it seems that proper shaping and added folding (if necessary) contribute a lot more to final loaf volume than extensive mixing or a long initial knead.
In fact, I've taken to running experiments in the past few months, making a lot of familiar recipes, but skipping the mixing/kneading beyond getting the ingredients moist and well-mixed. I add in a couple extra folds during bulk fermentation as necessary to achieve the kind of dough strength I want.
And, in the end, I don't feel like loaf volume is smaller. If anything, it seems to be slightly larger than I've generally had. I haven't gotten around to side-by-side comparisons yet, though in any case, if some of my loaf volumes are smaller, the difference is not very significant. I haven't noticed a difference in flavor, though it certainly isn't worse.
But it seems to me that the only real trade-off is maintenance. In the traditional baking routine with up-front mixing and kneading, I spend 5-10 minutes doing serious initial mixing. In the "no-knead" (or perhaps "minimal knead") case, I'm forced to tend to the dough for a couple minutes for every 45 minutes or even more often during bulk fermentation. While that additional maintenance can be bothersome, I'm generally already tied down for one or two folds anyway, and if I do an autolyze, that extends my initial time commitment as well.
So, in sum, I guess I have two questions:
(1) Is there something I'm missing here? Is there a major advantage to enhanced initial mixing, either something you've read about theoretically or something you've observed in your own baking?
(2) If the advantages aren't that significant, why is the standard method found in the vast majority of books so focused on a long initial knead/mix?