Can I Sous Vide in a Mason Jar? Egg Bites and Custard Jars
Can I sous vide in a mason jar? Yes, with care. Learn the right jars, finger-tight lids, temps for egg bites and custards, and why steak is better in a bag.
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The short answer
- Yes, with the right jar: heat-tolerant glass, lids only finger-tight, and the jar lowered into a preheated bath.
- Jars suit eggs and desserts: egg bites and custards are the classic uses, typically held around 170-180°F in published recipes.
- Steak and chicken fit a bag better, since the jar slows heat and the food cannot lie flat.
On this page
Can I sous vide in a mason jar? Yes, for foods that suit a jar: egg bites, custards and other soft dishes cook well in glass, held finger-tight in a bath at a steady temperature. Steaks, chops and chicken do better in a bag, which is why we rank the best sous vide machine for jar cooking and bag cooking alike on temperature control, not on the container.
Is it safe to sous vide in a mason jar?
Usually yes, if you respect glass. Canning-jar makers’ general guidance warns against sudden temperature changes, because glass can crack when it swings quickly from cold to hot. So preheat the bath, lower jars in slowly, and never move a hot jar into cold water. Sous vide baths sit well below the boiling-water heat canning jars are made to handle, so heat itself is rarely the problem; the sudden change is.
Glass rules for a bath
Use jars made for heat, such as canning jars, and skip any with chips or hairline cracks. Do not drop room-temperature jars into a bath near its target heat, and do not shock hot jars in ice water. Check your cooker manual for its own guidance on glass, and watch jars in a bath that runs for hours.
Should the lid be tight or loose?
Finger-tight, meaning snug but not cranked. General canning guidance calls this the usual setting for jars that heat in water, because air inside expands as the jar warms and needs a way out. A lid forced on hard can strain the glass or trap pressure, and a very loose lid lets bath water in.
A jar is not a vacuum seal. The food inside is cooked, not canned, and the USDA’s canning guidance is built around processing times that a sous vide bath does not provide. Cool it fast and keep it in the fridge. For bag-based sealing, see our guide on whether sous vide needs a vacuum.
What can you cook in a mason jar?
The classic jar foods are egg bites, custards, crème brûlée and similar desserts, because they are soft, portioned and eaten from the jar. Typical published recipes for these land around 170-180°F (about 170-176°F for egg bites and 176-180°F for custards), well above the temperatures for meat. Treat them as recipe-typical ranges, not fixed rules. Yogurt, oatmeal and some grains also work in a jar, though they are not protein cooks.
| Food | Bath | Jar fit |
|---|---|---|
| Egg bites | 170-176°F | Great |
| Custard | 176-180°F | Great |
| Chicken breast | 140-150°F | Poor |
| Steak | 129-134°F | Poor |
Eggs and custard run hotter than meat, which is part of why they suit a sealed jar.
How do you sous vide egg bites and custard in jars?
Fill each jar about three-quarters full to leave headroom, since egg mixtures puff slightly as they set. Screw the lid on finger-tight, set the jars upright in a preheated bath so the water reaches the neck, and cook until set. Chill promptly if you will not eat them right away.
- Preheat the bath to the recipe temperature.
- Pour the base into clean jars, leaving headroom.
- Close the lids finger-tight.
- Lower the jars in slowly, upright, with a rack if you have one.
- Cook for the recipe time, then lift out and cool.
Keep jars from floating
A jar with air in it floats and tips. Stand jars in a rack, wedge them against the container wall, or add a weight, and keep the water level high enough to reach the lid. A jar that floats sideways cooks unevenly.
Can you sous vide meat in a jar?
You can, but it is rarely the best choice. A bag lies flat against a steak and conducts heat evenly, while a jar traps air around food and slows heating, so thick or stacked pieces take longer to reach temperature. Food-safety pasteurization tables count hold time only once the center reaches the bath temperature, so a slower jar stretches the risky warm-up for chicken and pork.
Use the bath temperatures from our other guides, 129-134°F for medium-rare steak and 140-150°F for chicken breast, and only use jars for small, cut-up pieces such as chicken bites in sauce. Keep raw food refrigerated until it goes in, and follow published time and temperature tables.
Is a jar better than plastic?
Jars avoid disposable plastic, and many cooks like them for portioned desserts and egg bites. They do cost more attention: glass can crack, jars float, and heating is slower. A reusable silicone bag is another option if you want to skip single-use plastic and still cook meat flat.
A good cooker holds the bath within a degree or so, which matters more for egg texture than the container does.
Next in this series: Why Can't You Put Garlic in Sous Vide? Safety and Flavor
Frequently asked questions
Do mason jars vacuum seal?
Not for sous vide. A finger-tight lid lets expanding air escape, and the bath does not create a vacuum seal like a pump. Treat jar-cooked food as refrigerated food, not shelf-stable canning.
Is there a non-plastic sous vide?
Yes. Heat-tolerant glass jars and reusable silicone bags both avoid disposable plastic. Check the maker's guidance for the temperature you plan to hold.
Why do mason jars float in sous vide?
The trapped air inside makes the jar buoyant. Fill the jar, keep the water above the food line, and weigh it down or rack it so it stays submerged.