Okay... Do your 10 day old doughs have a funky smell? Today I took out a 5 day dough and plopped it on some flour and I knew I smelled something funny. I leaned down and smelled it, and it smelled like Natural Light. No joke! I understand some doughs last longer than other, but what is the secret? More sugar? Less yeast? Thanks.
A lot of my dough experiments have been done using a lidded metal container to store the doughs in the refrigerator. Normally, I would check them daily by removing the lid. In those instances, I could not detect any pronounced odors of fermentation. But when I sealed the doughs shut in the metal containers for several days in a row, or when I sealed a dough ball in a FoodSaver plastic storage bag for 15 days, I could definitely detect the odors of fermentation when I exposed the dough balls to the open environment. Having experienced these odors many times before, I don't deem the smells to be "funky". Maybe I did when I first experienced the odors, but that was a very long time ago.
I agree with chiguy that keeping the dough cold as much as possible, along with using small amounts of yeast, are two important contributors to dough longevity. However, it seemed to me that when I added the yeast (IDY) to the dough at the end of the dough making process, together with the salt, rather than at the beginning, the doughs seemed to have longer useful lives and with very good finished crust characteristics considering the ages of the doughs. And, for some reason, IDY seemed to work better than ADY (nonrehydrated) in terms of extending the dough's useful life. I added no sugar, so sugar was not a factor.
I also did a lot of other things up front to make a better quality dough, such as using sifted flour, the three different KitchenAid attachments, etc. Whether doing these things helped extend a dough's useful life is hard to say, but they certainly did not hurt matters. Doing these kinds of things did allow me to use hydration levels of around 65% without adversely affecting extensibility, which has long been a problem for many people with a dough like the Lehmann dough where it would be unusual to get more than 3 or 4 days without the dough becoming difficult to handle.