To find out which bags are least likely to spill the beans, cookies, or leftover sauce by ripping or dripping, we tested 20. Some had press-to-seal tops, others used zipping sliders. Most hold 1 gallon. (Hefty OneZip Fresh Extend, whose packaging states "helps keep a variety of fruits & veggies fresh," holds 1.25 gallons.)
We used a machine to test strength. To test leakage, we took three of every bag, poured 4 cups of water into each, sealed it, turned it sideways and upside down, and dropped it. We also stuffed bags to the brim with foam, tested moisture permeation, and checked whether any bags were especially good at keeping strawberries and green peppers fresh in the fridge. To check for freezer burn, we packaged steaks in all of the bags, squeezing out the air inside, and froze them for more than six weeks. And three panelists assessed convenience.
In a nutshell:
For storage bags, try the Glad or Up & Up press-to-seal or the Great Value or Up & Up slider. Best freezer bags include two of the Up & Up brand and the Glad press-to-seal.
For a bag that sits upright, consider a Ziploc expandable-bottom bag. Another option is Ziploc Evolve, which is claimed to use 25 percent less plastic than comparable Ziplocs and to be made using wind power. It was indeed thinner than other storage bags, but it's pricey and of average strength.
Whatever the bag, check unit prices. The number of bags per box differs widely and affects the cost per bag.