How to Get the Sour Smell Out of Towels (and Keep It From Coming Back)

The boil reset (white 100% cotton only)

1. 1

   Set up a safe pot

   Use a stainless steel or enamel stockpot, never aluminum, since the washing soda label says not to use it on aluminum. Pick a pot big enough that the towel and water fill no more than about two thirds of it. Then turn on your stove’s fan, and keep kids and pets out of the kitchen until you are done.

2. 2

   Measure water and washing soda

   Fill the pot with water and count as you go: 4 quarts is 1 gallon. Put on gloves and stir in 2 tablespoons of washing soda for every gallon. A 12 quart pot filled to two thirds holds 2 gallons, so that pot gets 4 tablespoons.

3. 3

   Add the towel, then bring it to a boil

   Put one or two towels in while the water is still cool, and push them under with tongs. Then turn up the heat. When the towels go in before the water boils, you are not dropping anything into a hot pot, so nothing splashes up at you.

4. 4

   Boil for 15 minutes

   Once it reaches a rolling boil, set a timer for 15 minutes. Turn the heat down so it boils gently without foaming over. Towels puff up with trapped air, so press them down with the tongs now and then. Never walk away and let the pot boil dry.

   What it looks like when it is working: watch the water. It often turns cloudy or yellowish as residue comes out of the towel, and that is exactly what you want to see leave.

5. 5

   Let it cool, then lift it out

   Turn off the heat and let the water cool until you could hold a gloved hand in it comfortably. Then lift the towel with tongs into a clean sink or bucket and pour the water down the drain.

6. 6

   Wash and dry it right away

   Wash the towel in the hottest water its label allows, with your usual detergent measured to the line. Leave out the fabric softener. Then dry it completely, right away, in the dryer or hung open.

The soak reset (colored towels, blends, or no big pot)

1. 1

   Dissolve the powder

   Put on gloves. Fill a clean bathtub, laundry tub or big bucket with warm to hot tap water, never boiling, as the maker says. Stir in the oxygen bleach powder: the OxiClean Versatile label says fill the scoop to line 3 for each gallon of water. Let it dissolve all the way before the towels go in.

2. 2

   Soak 1 to 6 hours

   Push the towels under so they are wet all the way through, and leave them 1 to 6 hours. If the smell has been hanging on for months, give it the full 6. On colored towels, test a hidden corner first. The label says the powder is for colorfast fabric only, meaning fabric whose color does not run.

3. 3

   Wash hot, with a booster

   Move the towels to the washer without rinsing. Add oxygen bleach powder to the drum before the towels go in (for a regular load, the label says fill to the bottom of line B). Then wash in the hottest water the label allows, with your usual detergent measured to the line and no fabric softener.

4. 4

   Dry right away, all the way

   Get them into the dryer or hung open as soon as the cycle ends. A wet load sitting in the washer gives the smell a head start.

How to tell it worked

Your nose is the test here. Smell the towels when they first come out of the washer, still damp, because that is when a sour towel gives itself away. If they smell like nothing at all, you are done.

Then check again after the first use, and again after the first day hanging in the bathroom. If the sour smell is back within a couple of uses, go to “When it will not work” below.

The three habits that keep it gone

The reset clears the smell out. These three habits keep it from moving back in.

1. Measure your detergent. Fill the cap to the line and stop there. Speed Queen, a washer maker, says too much detergent leaves residue that keeps towels from drying well and gives bacteria a place to live. If you see suds left after the rinse, you used too much.
2. Skip fabric softener on towels. It seems like softener would make towels softer. But the same maker says it builds up on towels and makes them less soft and less absorbent over time.
3. Dry them fast and all the way. Hang towels open between uses, and never put a damp towel in the hamper. Laundry research found that slow drying leaves more bacteria on fabric.

When it will not work, and what to do instead

Sometimes the smell comes back, or never quite leaves. Here is what to check.

• The towels smell fine, then sour again in a few days. That means the reset worked and a habit is bringing the smell back. Go over the three habits above, and wash towels often. Speed Queen suggests using a towel no more than three times between washes.
• Freshly washed towels smell like the washer. Run a clean washer cycle at least once a month or every 30 washes, and leave the door or lid open between loads. That is Whirlpool’s advice, because the washer itself can hold the smell: standing water inside a washer feeds bacteria and mold.
• You want to try vinegar. Keep it out of the washer. Maytag, a washer maker, says vinegar’s acid can wear down rubber seals and hoses over time, especially in front loaders. If you still want to try it, soak the towels in a tub instead: Maytag suggests 1 cup of vinegar in warm water for about 30 minutes. Rinse them well before they go back in the wash, and never add washing soda, oxygen bleach or chlorine bleach to that tub.
• Your towels are microfiber or a blend. Skip the boil entirely. Use the soak reset at the tag’s temperature.

Why it works

That sour smell is not dirt you can see. Scientists who studied towels in daily use found that bacteria build slimy little colonies deep in the woven base of the towel, down under the soft loops. Those towels started to smell after about two months of normal use.

Another research team linked the smell of washed laundry to one bacterium in particular. They found that cool, quick washes do not clear those bacteria, the skin oils they feed on, or the smell itself. Washes at about 122°F and up generally do.

That is why the fix is heat. It is also why the boil works so well on white cotton: boiling water is far hotter than any washer’s hot setting.

A towel that smells is not a sign you keep a dirty house. Most of the time it means somebody was trying to do right, maybe saving a little on the power bill with cold water, or adding an extra splash of soap to be sure. Those are good instincts pointed the wrong way.