How long does sous vide caramelization take?

Sous vide caramelizes onions more slowly than stovetop methods, typically requiring several hours at 185–195°F for full color and flavor development.

Can I use white or red onions instead of yellow?

Yellow onions are preferred for their higher sugar content and mild flavor; white onions work but caramelize less sweetly, and red onions turn muddy in color.

How do I know when caramelized onions are done?

They should be deeply golden to brown, soft enough to break with a spoon, and smell rich and sweet with no sharp onion bite.

How far in advance can I make caramelized onions?

Caramelized onions keep refrigerated in an airtight container for up to 1 week, or frozen for up to 3 months; reheat gently on the stovetop or microwave.

What's the purpose of balsamic vinegar and sugar in this recipe?

Balsamic vinegar adds depth and mild acidity to balance sweetness, while sugar accelerates caramelization and enhances browning.

Caramelized Onions (Sous Vide Method)

Name: Caramelized Onions (Sous Vide Method)
Prep time: 20 min
Cook time: 6 h
Total time: 6 h 20 min
Yield: 4 servings
Ingredients: 1 tbsp unsalted butter; 1 tbsp olive oil; 2 lbs yellow onions; 1 large sprig fresh thyme; 1 tbsp balsamic vinegar; ¼ tsp granulated sugar; ¾ tsp salt; ½ tsp black pepper

1

If using a sous vide immersion circulator, pre-heat your water bath to 185°F (this can take up to an hour)

2

Peel onions, trimming roots to keep them slightly intact, halve onions lengthwise, and slice (from root to base) into thin ¼-inch wedges

3

Heat a large skillet over medium heat. Add 1 tbsp butter, 1 tbsp olive oil, and once butter has melted, add 2 lbs sliced onions, 1 large sprig fresh thyme, 1 tbsp balsamic vinegar, ¾ tsp salt, ½ tsp black pepper, and ¼ tsp granulated sugar, and occasionally stir until the onions pick up a little color and become slightly translucent, around 6 to 8 minutes. Remove from heat and allow to cool slightly. Discard thyme sprig

4

Transfer onions to a vacuum bag or resealable bag and seal bag (if using Suvie, you may want to divide between 2 bags to ensure they fit in the pans). If using a resealable bag, use the water displacement method to seal

5

Lower the bag into the heated water bath and cook. Cover the water bath with foil, cling wrap, or a layer of ping pong balls, to avoid the water evaporating to sustain the high water temperature. If using Suvie, place the bag into a Suvie pan (or pans) and cover entirely with water. Insert pan into the top or bottom of your Suvie. Set to Sous Vide at 180°F for 6 hours

6

Once the cook is finished, remove the bag from your Suvie or water bath. Drain onions in a fine-mesh strainer to remove excess moisture. You may wish to add another ¼ to ½ tsp salt to taste