Can you use a sous vide for yogurt?

Yes — and if you already own a circulator you should not buy a yogurt maker at all. If you do not own one, the Anova Precision Cooker Nano 3.0 is the pick: it is the cheapest device on this page that publishes a temperature accuracy figure, and accuracy is the entire job. For someone who wants one switch and no thinking, a dedicated yogurt maker like the Euro Cuisine YM80 is still the easier object to live with.

Yogurt is the simplest ferment we cover. There is no airlock, no weight, no shaping and no SCOBY. There is milk, a spoonful of live culture, and a temperature held steady for hours. Which means the only question worth asking about the hardware is how well it holds a temperature — and on that question, the specialist appliance loses to the general-purpose one.

The number, and who publishes it

Yogurt incubates at about 110F (43C). America’s Test Kitchen holds a 110F bath for five to twenty-four hours; Anova’s own recipes use 109.4 to 110F for five to twelve. Shorter is milder and looser, longer is tangier and thicker. The milk is heated and then cooled to 110F before the culture goes in, because residual heat kills the bacteria you just paid for.

Now the part that decides this page:

• Anova publishes a range and a tolerance. For the Nano line: 32 to 197F, accurate to plus or minus 0.2F (0.1C), 8 liters a minute of flow, two-year warranty.
• Yogurt makers publish neither. Across our yogurt maker roundup and Greek yogurt page, no manufacturer states how tightly its appliance holds its setpoint. Most do not publish the setpoint itself.

So the circulator is not merely adequate at this. It is the only appliance in the category whose maker will tell you, in writing, what it does. That is the same argument we end up making about proofing boxes and kimchi fridges: in temperature-controlled appliances, published tolerance is rare and worth paying attention to when you find it.

Why circulating water is genuinely better

A yogurt maker is a warm box. Heat comes from an element at the base or the side, and the jars nearest it run warmer than the jars furthest from it. With seven small jars that is usually fine. It is also why some makers produce one jar that sets differently from the rest.

A water bath removes that problem physically. Water conducts heat far better than air, and a circulator moves it continuously, so every jar sits in the same temperature. There is no warm side to the batch and no hot spot against the element.

How we picked

Criteria first, as always:

• Is an accuracy figure published? The whole premise of using a circulator is precision. A circulator that does not publish its tolerance has given up its only advantage.
• Does it reach 110F comfortably? All of these do; it is the bottom of their range, not a stretch.
• What does it cost against a yogurt maker? And what does it do on the other days?
• What does the user have to supply? This is where the circulator loses, and we have not hidden it.

The honest case against doing this

A yogurt maker is one switch. A circulator is a set point, a deep enough vessel, a water level above the minimum line, jars that will not float, and lids left loose so gas escapes. None of it is difficult. All of it is more steps than pressing a button, and more steps is how a weekly habit becomes a monthly one.

Three specific frictions worth knowing before you buy:

• Jars float. Milk is less dense than water; a part-filled jar will tip. You need a rack, a weight, or clips.
• Your pot may be too shallow. A circulator has a minimum water line it must reach, and many saucepans do not reach it with jars taking up the floor space.
• Lids stay loose. Tightened lids trap fermentation gas. Loose lids in a water bath mean being careful about the water line.

The method, start to finish

Nothing here is specific to a circulator except the bath. The sequence is the same one any yogurt uses.

• Heat the milk to about 180F and hold it briefly. This denatures the whey proteins, which is what makes a thick set rather than a thin one. Skipping this step is the usual reason homemade yogurt is loose.
• Cool it to 110F. Not approximately — this is the step that kills cultures. Residual heat above about 115F damages the bacteria you are about to add.
• Stir in the culture: a few spoonfuls of live yogurt, or a powdered starter. Whisk it smooth into a little of the milk first, then into the rest.
• Into jars, lids on loose, and into the bath at 110F. Weight or clip them so they cannot tip.
• Five to twelve hours. America’s Test Kitchen goes as far as twenty-four for a markedly tangier result. Shorter is milder and looser.
• Chill for at least four hours, ideally overnight, before you judge it.

Three things that go wrong

It came out thin. In order of likelihood: you judged it warm; you skipped the 180F hold; the milk was ultra-pasteurized; or the culture was old. The bath temperature is the least likely cause when a circulator is holding it, which is rather the point of using one.

A jar tipped and took on water. Milk is less dense than water and a part-filled jar is buoyant. Weight them, clip them, or stand them in a rack.

It is too sour. Shorten the incubation. Sourness is a direct function of time at temperature, and five hours and twelve hours are genuinely different products from the same ingredients.

The milk matters more than the machine

Worth saying on a page about appliances: the biggest variable in homemade yogurt is not the device. Whole milk sets thicker than skim. Ultra-pasteurized milk behaves differently from pasteurized and is the usual culprit behind a batch that will not set at all, because the protein structure has already been altered by the heat treatment.

Before you blame hardware for thin yogurt, change the milk — the same advice we give for Greek yogurt and for milk kefir. A circulator holding 110F to a tenth of a degree cannot fix the wrong milk.

Side by side

What else a circulator does for a fermenter

This is the part that changes the value calculation, and it is why we rank the circulator first for anyone who does not already own a yogurt maker. A thermostat that holds any temperature between 32F and 197F to a published tolerance is useful well beyond yogurt:

• Reviving a dried culture. Any of the dehydrated cultures we cover want a steady warm spot for their first days, and a water bath is the steadiest one in a kitchen.
• Holding a kefir or a long culture through a cold kitchen, where a counter in February is the actual problem.
• Pasteurizing milk precisely before culturing, which is the 180F step above, in the same vessel.
• Cooking, which is what it was sold for.

A yogurt maker does one thing. That is a feature when the one thing is all you want, and it is the reason we have not simply declared the circulator the winner.

The cost question, honestly

A basic yogurt maker and an entry circulator are closer in price than people expect, and the circulator is not always the more expensive of the two. What separates them is not really money:

If you cook, the circulator is the better buy at almost any price difference, because it is an appliance you will use on days you are not making yogurt. A yogurt maker sits in a cupboard between batches.

If you do not cook, the yogurt maker is the better buy even when it costs the same, because the five setup steps are a tax you pay every single time and it compounds. The device that gets used is worth more than the device with the better specification.

If you own neither and are not sure you will keep doing this, buy nothing this week. The oven light will tell you whether yogurt is a habit for about zero dollars, and our first-batch troubleshooting page covers what to expect from a less controlled first attempt.

What we would do

If you own a circulator: make yogurt in it tonight and buy nothing. Set 110F, cool your scalded milk to 110F, stir in the culture, loose lids, weight the jars, five to twelve hours.

If you own neither: the Nano 3.0 if you also cook, because the price difference against a yogurt maker buys an appliance that works all week. The Euro Cuisine YM80 if you want one switch and nothing else — it is a perfectly good machine and simplicity is a real feature.

If you want thick Greek-style yogurt, note that neither device gets you there on its own: that is a straining step, and our Greek yogurt page covers the strainers.