How long do you let onion water sit before drinking?

The common practice of preparing onion water, whether for home cold and flu remedies or purported general wellness, often circles back to a fundamental question: how long does this liquid need to steep or sit before it is ready for consumption? Unlike a cup of tea that benefits from a few minutes of infusion, the recommended waiting period for onion water varies significantly depending on the desired outcome and the specific preparation method employed, ranging from immediate consumption after a quick boil to prolonged soaking periods spanning days. ^[1][2][3][5]

# Steeping Time Variances

The duration an onion needs to sit in water before drinking is not a single, fixed answer; it depends heavily on whether you are making a hot infusion or a cold, extracted tonic. ^[6] For those seeking relief from cold or flu symptoms, some methods involve boiling the onions, which drastically shortens the required waiting time. ^[3][7] If you boil the onions in water and then simply let the liquid cool to a drinkable temperature, you can theoretically consume it relatively quickly, perhaps after a short cooling period of about 10 to 20 minutes, to maintain a warm temperature for comfort. ^[3]

Conversely, many traditional or TikTok-popularized methods rely on cold infusion, which demands a much longer sitting time to draw out the beneficial compounds from the onion cells. ^[1][2][8] One approach involves chopping or slicing raw onions and covering them with water, sometimes adding a sweetener like honey or sugar, and allowing this mixture to sit overnight. ^[1] This overnight wait is particularly associated with creating an onion syrup, where the water extracts the essence of the onion into a potent liquid, often yielding enough to drink across several doses the following day. ^[1] For those simply soaking raw onion slices in plain water, letting it rest for several hours, perhaps 4 to 6 hours at room temperature, might be sufficient to impart a noticeable flavor and alleged benefits, although longer soaking times usually result in a stronger concentration. ^[2][8]

A significantly different timeline applies when onions are soaked in vinegar rather than water. In this context, the goal shifts, and the preparation requires a much more substantial commitment, often needing to sit for a minimum of 24 hours before the vinegar-soaked onion water is consumed, sometimes on an empty stomach for specific purposes. ^[5]

This variance suggests that 'sitting time' can refer to three different processes: cooling time after boiling, infusion time for cold extraction, or maturation time for vinegar soaking. ^[1][5][6]

# Preparation Method Influence

The preparation method dictates the necessary sitting time because it affects the rate at which water-soluble compounds are released from the onion's cellular structure. ^[1][6]

# Boiling Versus Soaking

When onions are boiled, the heat breaks down cell walls rapidly, releasing flavors and compounds quickly into the water. ^[3] Therefore, the sitting time is minimal—primarily dictated by safety and preference for temperature. You are waiting for it to stop being scalding hot, not waiting for maximum extraction. ^[3][7]

Cold soaking, conversely, is a passive extraction process. The water must slowly permeate the onion layers. To achieve a concentration that feels meaningful to the drinker, a longer duration is necessary. ^[2][8] If you are aiming for a mild, lightly flavored drink, a couple of hours might suffice. However, if the goal is to create a recognized cold remedy, the liquid often needs to develop a stronger, more pungent character, which usually requires an extended sitting period, often overnight. ^[1]

# Vinegar Infusion Timelines

It is worth noting how the choice of soaking liquid alters the timeline entirely. Soaking onions in vinegar, a distinct preparation, is not about quick relief but about creating a different kind of tonic. ^[5] The chemical properties of acetic acid in vinegar draw out compounds differently than pure water, necessitating that extended minimum 24-hour period for proper flavor melding and compound transfer. ^[5] This preparation is typically tied to specific traditional uses, such as consuming the mixture on an empty stomach. ^[5]

To help clarify the different expectations readers might have based on their goal, here is a quick comparison of the common waiting times associated with different onion water preparations:

When you consider a standard 8-hour sleep cycle, letting the onion water sit overnight—say, from 8 PM to 7 AM—provides a reliable 11-hour window for significant compound extraction in a cold soak, which often yields a stronger result than just a few hours on the counter. ^[1][8]

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# Storage and Freshness

Once the desired sitting time has passed and you have separated the liquid from the onion solids—especially in the case of the syrup created by overnight soaking—the next consideration is how long the resulting onion water can continue to sit before it should be consumed or discarded. ^[4] Since onion water is essentially a fresh infusion containing organic matter, it is perishable and should not be left indefinitely at room temperature. ^[4]

For optimal safety and potency, it is widely recommended that prepared onion water, particularly the cold-soaked variety, be refrigerated immediately after the steeping period is complete. ^[4] Storing it in an airtight container in the refrigerator extends its usability. While some anecdotal reports suggest it can be kept for several days, a safer general guideline, assuming good hygiene in preparation, would be to consume it within 3 to 4 days. ^[4] If the liquid appears cloudy, develops an off-smell, or shows any sign of fermentation (like bubbles), it should be discarded immediately, regardless of how long it has technically been sitting. ^[4]

A practical application of this is planning your infusion schedule. If you plan to drink a glass each morning for your cold remedy, preparing a batch large enough for three days on a Sunday evening ensures you always have a fresh, potent dose ready without pushing the limits of safe storage. ^[4]

One factor that subtly influences how long you should let it sit for flavor reasons is the inherent pungency of the onion itself. If you are using a particularly sharp variety, like a potent red onion, an 8-hour soak might already produce a very strong flavor. If you push that to 24 hours, the taste might become overwhelmingly sulfurous for daily consumption, even if the beneficial compounds are technically more concentrated. This trade-off between concentration and palatability is something every home preparer must manage based on their personal tolerance for onion flavor. ^[2]

# Immediate vs. Extended Sitting

The perceived need for extended sitting time often relates to maximizing the sulfur compounds, which are believed to be responsible for many of the purported health effects, such as easing cold symptoms. ^[2][6] Sulfur compounds are volatile; boiling drives them out quickly (which might mean you lose some benefit), while cold soaking preserves them over time but requires patience. ^[6][7]

If you are in immediate need of a warm drink—perhaps you just started feeling a scratchy throat—the boiled method is superior because it allows for consumption within minutes of cooling down. ^[3] In this scenario, the "sitting time" is just cooling time.

However, if you are engaging in a preventative or longer-term regimen, the extended sitting time of a cold soak allows for a more gradual extraction, which some proponents feel results in a smoother, more beneficial tonic. ^[8] For instance, a TikTok video demonstrating this remedy suggests drinking the prepared water the next day, indicating an intention to let the soak continue for a minimum of 12 hours. ^[8] This aligns well with the overnight infusion concept, where you prepare it before bed and drink it the next morning.

Ultimately, while there is no single consensus on the perfect resting period, the evidence points toward using time—whether a few hours for a mild taste or overnight for maximum extraction—as a variable you control based on your immediate needs and tolerance for the resulting flavor intensity. ^[1][2][5] The decision to let it sit longer than necessary is usually one of flavor preference rather than a strict requirement for chemical activation, with the exception of the vinegar preparation. ^[5] Always err on the side of caution regarding storage time once the infusion is complete, favoring refrigeration and shorter storage windows for the water-based preparations. ^[4]