A company spokeswoman told the WSJ, "We regularly service our soft-serve equipment during off-peak hours. Customers who come in during that time may encounter a longer wait time or soft-serve dessert unavailability."
But a McDonald's employee gave the Journal the inside scoop, and claimed it was even more complicated than that. According to the machine's manual, the 11-part cleaning process "involves combining a sanitizing mix with warm water, removing and rinsing seven parts, brushing clean two fixed parts for 60 seconds and wiping down the machine with a sanitized towel."
The employee said that often if a guest orders ice cream late at night -- when the machine is more likely to be prepped for cleaning -- they'll often say the machine is "down," rather than reassemble it. Who could blame them?