Peel and cut in quarters as many potatoes as you have guests. Typically 1 large or 2 smaller potatoes per person. Place in a large pot and fill with water half way covering the potatoes. With lid on, heat over medium high heat until boiling. Turn down to low medium, you want it to continue to boil but not to the point that it boils over your pot. Continue cooking for about 20 minutes. Test the potatoes by poking with a fork, if soft—then done. With lid on drain out liquid from pot, being careful not to burn yourself from the steam. After liquid is drained out, put in 1-16 oz container of sour cream for 10 lbs of potatoes. Use an electric mixer on high and beat potatoes until smooth. Make sure to get down in all of the corners of the pot when you are mixing.