I was thoroughly impressed with the way Heinz handled the situation. When I went back to their Facebook page later in the day, Heinz quickly responded to the issue. They reported that they were unsure as to what caused the glitch, but that anyone who had trouble placing an order could order now and Heinz would add an additional bottle for free and free shipping.
Obviously, giving away free products and free shipping is very costly (especially to a small business). If you have a similar situation (whether it's online or not), take a cue from Heinz-- respond quickly and offer your sincerest apologies. If you can, throw in an apology gift to keep those customers coming back (but be sure not to break the bank) like a coupon, discount, reduced or free shipping, or free samples. You always want to keep those customer relationships strong!
As a small food or farm business owner, have you ever had a problem (whether it's web ordering, product shortages, etc) that has kept you from filling orders? How did you handle it? Did you manage to save the relationships with your customers?
