Pizza dough is a handy thing to keep in the freezer. Whether you use it for its intended purpose, or convert it into garlic fingers, calzones or bread sticks, you always have options with that portion of dough at your fingertips. Occasionally, you might find yourself with dough you've thawed -- deliberately or accidentally -- and won't use. It can often be refrozen for later, though its quality will vary.
In a discussion of which foods remain safe after a power outage, the U.S. Food and Drug Administration says that yeast doughs can be refrozen, but that "quality loss is considerable." That's certainly true in the case of a lengthy power outage, but won't necessarily be the case if you've thawed the dough deliberately.
The yeasts that make pizza dough rise become dormant in the freezer but revive quickly at room temperature. Once they're awake, they quickly go back to their job of converting sugars in the dough to carbon dioxide and alcohol. This process is called fermentation. If it goes on too long, the dough will quickly develop a sour smell and coarse texture. That's why the FDA warns of a significant loss in quality.
Be wary of the risk of considerable quality loss.
The secret to successful refreezing, then, is simply to not let the dough reach room temperature. Instead of taking it out and resting it on the counter to thaw, defrost it in the refrigerator. A slow overnight or all-day thaw in the refrigerator keeps yeast activity to a minimum, partly because thawing is so much slower and partly because the yeasts remain sluggish at refrigerator temperatures.
The dough will still be ready to use when you get home from work, but -- if your plans change -- it will refreeze with good results. Simply flatten the dough, if it has risen noticeably, and return it to the freezer.
If your frozen pizza dough is homemade, it's best to freeze dough after its first rise. The yeasts are still working at that point, so even after thawing and rising in the refrigerator they won't have opportunity to over-ferment the dough.
Tips
If you haven't made dough for the freezer before, you might make the novice error of freezing the dough in a single ball. That means thawing it every time you want a meal's worth of dough, which is never a good thing.
Instead, divide the dough into portions and press it out into pizza-sized discs. Bag them individually in single bags between sheets of wax paper -- so they don't stick to the bag -- or layer them in a single large bag, with sheets of wax paper in between. When you want to make pizza, take out a single round of dough to thaw. This way, if you need to refreeze it, you won't be affecting the others.