Why does my pizza dough (and other doughs) go sticky on freezing and defrosting? I make this simple sourdough pizza dough, with the slight variation that I weigh my starter.  A half quantity does me 2 pizzas.  So that's 150g 100% hydration starter, 125ml water, 250g flour, kneaded in a stand mixer and rested (30 minutes to 2 hours depending on my evening).  That gives me a nice easy to work dough.  But I only want to make one pizza, so I freeze half of the dough - I roll it into a ball, roll it in flour, and put it in a generously floured plastic container, then freeze for about a week.
When I defrost it (in the fridge for 24 hours), it's always stickier and harder to work with than it was before freezing, despite having added a little flour in the dusting.  The resulting pizza is just as good though (fairly thin, baked at 240°C on a slab of preheated granite).
It happens consistently, and I've noticed the same with naan dough.  The last 2 batches of pizza dough I froze with a note about how easy they were to handle, to be sure I hadn't just made a sticky batch and forgotten by the time I defrosted it.
Why is this, and is there anything I can do about it?
There are several effects which I think are at work here:

starch hydrates over time. Sure, within an initial kneading, it already hydrates quite a bit, but if you leave it longer, it continues changing. (That's also why it is recommended to rest crepe batter). So the starch which was somewhat-dry is now completely wet, making the dough as a whole stick. If you had patches of completely dry flour on the outside left from shaping, they are now also completely wettened, giving you more initial sticking at your first touch of the dough, which probably contributes to the sticky impression even more.

24 hours is quite long for an already-risen dough, even though the temperature is very low (starts from frozen). I wouldn't be surprised if the overleavening process starts already in that timeframe, and overleavened dough is sticky.

the gluten mesh is susceptible to physical disruption. I mostly notice this with home-ground wholemeal flour, the bran basically cuts it too much for proper rising. I guess that the formation and expansion of ice crystals also has a bit of an effect on your gluten, even though it's milder because of the lack of kneading while the crystals are present.


So I think this is to be expected, and not exactly worrisome. If you want to reduce the effect, you can freeze the dough in discs instead of a cuboid or cylindrical container. You will then have shorter defrosting times, and your dough won't overleaven on the outside while the center is still defrosting.