There are only two of us, and my husband will not eat instant potatoes. So I make a 5 lb. bag of potatoes at once and have great success freezing them. I always use a yellow potato and I am careful not to make them too runny or liquidy - for 5 lbs of potatoes, I use 1 stick of butter and start with about a half cup of whole milk, adding a bit more as necessary. Although I put a little salt in the water while cooking the potatoes, I don't add any more salt to the potatoes while mashing - it will draw out the water so season them later. I mash them by hand, and leave them a little lumpy so that the potatoes don't break down too much. After dinner, when the potatoes have cooled, I spoon them into gallon size zip lock freezer bags and press them down so that they are flat and no more than a 1/2 inch thick. I press out all the air, and make sure the potatoes fill the bag. They store in the refrigerator great this way - you can stack them and they don't take much room at all. When I am ready to use them, I can break off the frozen potatoes without thawing them - that's why you press them down flat - (depending on appetite, half to 2/3 of a bag is enough for 2 people) and defrost and reheat them in the microwave on HALF POWER, 2-3 minutes at a time, stirring and breaking them up as necessary until they are ready to eat. If they look too liquidy, let them sit a minute, then heat again on full power for about a minute. I have served these potatoes to company and no one ever knows that they had been frozen.