Whenever I buy bread, it's flavor and texture is amazing in the first day. The bread is humid and soft. In 2 or 3 days, it gets hard. Is there some trick to renew the bread to a nicer state?
While it is never possible to restore bread to its fresh baked glory, toasting can help.
The main staling mechanism in bread is the re-crystalization of the formerly gelatinized starches, making the bread seem hard and dry.
Toasting heats the bread up, and helps the starches re-gelatinize, and so can help mitigate the staleness, although it is not a complete cure.
The trick I learned from my grandfather is harder to do these days because of the prevelance of plastic bags:
- Heat your oven.
- Wet down the inside of a paper bag.
- Place the loaf of bread in the paper bag, and fold it over to seal
- Place the paper bag in the oven.
- Extract it before the paper looks like it's getting crispy.
As rumtscho mentions in his comment, once it cools back down, it can firm back up, but I find that it'll take longer than just warming it up in a dry oven. (I don't know if it's an issue with extra heat being transfered in the water, so it takes longer to cool, or if there's something chemical going on).
And as I'll probably get questions about what oven temperature -- whatever temp you're baking everything else at. If you're not cooking anything else, try 300F / 150C ... it's most important to heat it up to generate steam on the inside of the bag, but not so hot that the bag combusts.
(white paper bags are better than brown in my opinion, as you can see 'em starting to char a little bit to signal when to remove them)