TL;DR
Wash yogurt maker jars and lids in hot soapy water first, then add a sanitizing step -- a hot water rinse, or a food-contact sanitizer used exactly as its label directs. Cleaning and sanitizing are two different actions, and sanitizing only works on an already-clean surface. The base holds the heating element and is wiped, never submerged.
Cleaning and sanitizing are not the same step
Cleaning removes soil. Sanitizing reduces germs on a surface that has already been cleaned. Disinfecting kills to a label standard and requires both a cleaned surface and a stated wet dwell time. Skipping the wash and going straight to a sanitizer does not work, because soil shields whatever is under it.
For a yogurt maker this matters more than for most appliances, because the whole point of the machine is to hold milk at a warm temperature for hours. Any residue left behind gets the same warm hours the culture does.
None of this is a health claim. Cleaning and sanitizing reduce residue and surface germs; they do not prevent or cure illness. Questions about food safety and your own health belong with a doctor or a public health source.
Source: U.S. Food and Drug Administration Food Code guidance on cleaning and sanitizing food-contact surfaces
How do you clean yogurt maker jars?
Rinse jars with cool water first to clear the milk film, because hot water sets protein onto glass and makes it cloudier. Then wash with hot water, dish soap, and a bottle brush, paying attention to the shoulder where the jar narrows. Rinse well, then finish with a hot water rinse and let them air dry upside down on a rack.
The cool-first rule is the same one that governs protein stains everywhere. Hot water on milk protein bonds it to the surface instead of releasing it.
Glass jars are usually dishwasher safe. Plastic jars often are too, but repeated hot cycles cloud and craze plastic over time, so handwashing extends their life.
The lids and the rings
Lids are where the milk film hides. Screw-on rings have threads, snap lids have a lip, and both trap a ring of dried dairy that goes sour and passes an off flavor into the next batch.
Wash lids separately, work the threads with a brush, and rinse thoroughly. If a lid has a silicone gasket that lifts out, take it out and wash the groove behind it -- that groove is the most common source of a smell nobody can locate.
Air dry lids fully with the gaskets out. Reassembling a lid while the groove is still damp restarts the problem. This is the same routine that keeps an ice cream maker bowl, paddle, and lid from souring.
Sanitizing without overdoing it
The simplest home sanitizing step is a hot water rinse after washing, followed by full air drying. Many people also scald jars with boiling water before a batch, which is fine for heat-safe glass -- pour it out and let the jars dry upright.
If you prefer a chemical sanitizer, use one labeled for food-contact surfaces and follow its label exactly, including concentration and dwell time and whether a rinse is required. A stronger mixture is not a better one.
Two hard rules apply no matter what you choose. Never mix bleach with vinegar, any descaler, ammonia, or rubbing alcohol in one container, because each of those combinations releases a toxic gas. And never use a sanitizer on a surface you have not cleaned first.
The base is wipe-only
The base holds the heating element, the thermostat, and the wiring. Unplug it and wipe the inside with a cloth wrung out in warm soapy water, then a clean damp cloth, then dry. Never fill the base with water unless the manual specifically says the model uses a water bath.
Spills that dry on the base plate scorch and smell every time the machine runs. Wipe them the same day.
Some models do use a shallow water bath. Those need descaling if you have hard water, the same mineral problem that shows up in an electric food steamer and water reservoir. Scale is mineral, not dirt, and it needs an acid rather than a scrub.
Milk film, cloudiness, and stubborn smells
A hazy film on glass after washing usually means the milk protein was hit with hot water before it was rinsed off. Soak the jar in cool water, wash again with dish soap, and it generally clears.
For a persistent sour smell in plastic, wash, rinse, and then let the part sit open to air in a dry place for a day or two. Plastic holds odor because it is slightly porous, and time plus airflow does more than any product.
Do not use strong solvents or heavily fragranced cleaners on food-contact plastic. The fragrance stays and ends up in the yogurt. Milk residue behaves this way everywhere, which is why a milk frother wand and jug gets cleaned within minutes of use.
A practical routine
Wash jars, lids, and gaskets after every batch. Wipe the base after every batch. Deep clean the base plate, the lid gasket grooves, and the vents monthly with regular use.
Store everything dry and loosely assembled so trapped moisture can escape. Jars stored capped tight while slightly damp are the classic source of a musty first batch.
If a yogurt maker is one item in a kitchen that has gotten away from you, a broader reset by house cleaning services is usually a better use of a Saturday than working through the counter one appliance at a time. General appliance rules live in the small appliance cleaning guide.
FAQ
Do you have to sterilize yogurt maker jars?
Home yogurt making does not require true sterilization. Wash the jars with hot soapy water, rinse well, and add a sanitizing step such as a hot water rinse or a scald with boiling water for heat-safe glass. Sanitizing only works after cleaning, so never skip the wash.
Can yogurt maker jars go in the dishwasher?
Glass jars usually can, and many plastic jars are top-rack safe if the manual says so. Repeated hot cycles do cloud and craze plastic over time, so handwashing extends their life. Lids with silicone gaskets are better washed by hand with the gasket removed so the groove gets cleaned.
Why does my yogurt maker smell sour?
Dried milk film in the lid threads, behind a silicone gasket, or on the base plate is the usual source. Remove the gasket, wash its groove, wash the lid threads with a brush, and wipe the base plate. Let every part air dry fully before reassembling, since damp parts restart the smell.
Can you use bleach to sanitize yogurt jars?
Only a product labeled for food-contact sanitizing, used exactly at the concentration and dwell time its label states, and never mixed with vinegar, ammonia, alcohol, or any descaler -- those combinations release toxic gases. For most households, a hot water rinse after a thorough wash is simpler and enough.
How do you get cloudy milk film off glass jars?
Soak the jar in cool water first, because hot water sets milk protein onto glass. Then wash with dish soap and a bottle brush, focusing on the shoulder of the jar, and rinse well. Repeating the cool soak once usually clears film that survived the first wash.
Can you put water in a yogurt maker base?
Only if the manual says your model uses a water bath. Most bases hold a heating element and wiring and must never be filled or submerged. On water-bath models, empty the bath after each batch and descale periodically if you have hard water, since mineral scale is not removed by scrubbing.
Dairy is the residue that finds every crack -- in the jar threads, on the counter, and on the fridge handle nobody wipes. Every home is different, so the real number depends on size, condition, and what you want covered. Get a quote and we will walk you through it.