Once you've squeezed all the juice out of a lemon, don't just throw it out. Toss the remainder in the freezer, and when you need to keep other foods fresh and bright, you'll already have a little acid water on hand for the job.
We've already explained how useful acidulated water can be -- just a little keeps apples, potatoes, artichokes and other fruits and veggies fresh. If you don't want to keep a container of acid water in the fridge all the time, keep a bag of spent lemons in the freezer. That way when you need acidulated water, you can grab one of them out of the baggie, soak it in water, and add what you need to keep fresh then -- there's still enough acid in that lemon to get the job done.
Alternatively, we've shown you how a little honey water can do the same thing, thanks to the wonder of chemistry. Whatever method you prefer, you'll never have to deal with browned apples or pears ever again.
5 Reasons Your Freezer Is Your Friend [America's Test Kitchen]