FAQ: Egg Washing

If you raise chickens, you get some dirty eggs. Is egg washing okay, and, if so, how? And how can you minimize the number of dirty eggs? Read on! I’ll cover the basic egg cleaning concepts, how to wash eggs by hand, and what you need to know about both homemade and commercial egg washing machines.

1. Is it okay to wash eggs?

It’s okay by me! Some jurisdictions have laws forbidding you to wash any eggs that you’re going to sell. Some have laws requiring that you wash any eggs you’re going to sell. I’ll go into that further on.

But face it, some eggs you collect from your flock will be too dirty to use unless you wash them first. You can always throw them away (and with the very worst ones, that’s often your best bet), but you’ll have plenty of eggs that are too dirty to use but not dirty enough to throw away.

2. Wait, aren’t eggs protected by a mystical-magical “bloom” that is removed by washing?

The “bloom” (or “cuticle”) is a mucous film on the outside of the eggshell. It’s nothing to get excited about, even if you’re into mucous.

But yes, it’s true that washing removes this slime layer. But the only real-world significance of the bloom is that washed eggs lose moisture a little faster than unwashed eggs. Producers used to put a very light spray of mineral oil on the eggs to reduce evaporation. As far as I can tell, no one can tell the difference if they keep their eggs in the refrigerator, and maybe not if they keep their eggs on the shelf.

Once, as an experiment, I kept some washed and unwashed eggs in my basement, unrefrigerated, for six weeks. I couldn’t tell the two groups apart. Both had declined to Grade B quality (runny whites, fragile yolks) but were still edible.

3. How do I wash dirty eggs?

There are only a few points you need to remember when cleaning eggs:

• The “dirt” on dirty eggs is usually manure. Thus, a dirty egg is likely to drop flakes of manure into your frying pan. I like my food natural, but not that natural. The outside of such an egg is obviously swarming with bacteria. A dirty egg will thus go bad faster than an egg that was never dirty.
• If the washing process draws live bacteria into the interior of the eggs, the eggs go bad as quickly as unwashed dirty eggs, and maybe faster.
• If the washing process keeps the bacteria on the surface, or kills them, or both, the washed eggs go bad as slowly as eggs that were never dirty, or even slower.
• When using cold water as part of the process, the cold water chills the egg and the egg’s contents contract. To fill this space, air, water, or dirt are sucked into the egg through the pores in the shell.
• But if the water is warmer than the egg, it causes the contents of the egg to expand, and air, water, or dirt are pushed out of the pores of the egg and into the wash water.

The take-aways are:

• Always wash eggs in water that’s significantly warmer than the eggs.
• Sanitize the eggshells to kill any bacteria on the shell. I rinse with diluted bleach. Some people prefer quaternary ammonia or even very hot water.

4. How should I wash eggs by hand?

Buying a commercial egg washer isn’t to everyone’s taste (or budget), so here’s an egg-washing technique that ought to be acceptable everywhere in the US, even by the strict USDA standards:

 

1. Clean your work area before starting, and have a trash container for paper towels and broken eggs, and make sure you have a sink nearby that’s not full of eggs, so you can wash your hands when they get dirty, which they will.

2. Get one or more large plastic watering cans.
3. Fill a watering can with water at about 100 °F (35 C), a little unscented detergent (you can buy “egg wash powder” or use unscented commercial dishwasher detergent), and enough bleach to bring the free chlorine to 100-200 ppm.  Chlorine test strips can be bought at any wholesale grocery or restaurant supply store.

4. With your dirty eggs in or plastic washer flats, water them generously with the watering can. Allow the water to go down the drain. Letting the eggs stand in water violates USDA rules (though this may not apply to you), and tends to give rise to the same problems seen in immersion washers, as discussed later on.
5. Let them sit for a couple of minutes. If the eggs are particularly disgusting, you might want to wet them again after a couple of minutes.
6. Take the eggs one at a time and wipe them with a paper towel. If the eggs are too dry to wipe clean, pour some of your unused wash water onto a clean paper towel. You can dip a brand-new towel in the water, but once the towel has touched and egg, don’t dip it again; we want to keep the water clean. Discard the towels as they become dirty. Cloth towels are against everyone’s rules because people keep using them after they’re dirty. Put the cleaned eggs into another wire basket or washer flat. You may want to have a separate area for stubborn eggs that need to be sprayed and rubbed again.
7. Next comes a sanitizing spray. A watering can with 100 ºF water and bleach at 100-200 ppm is good.  Don’t stint; use plenty of water. This gets them cleaner, and the bleach helps make the stains go away.
8. Dry the eggs in some responsible manner. They’ll stick to the cartons if you box them while wet. Some people dry them on racks, using ½ in. hardware cloth on a wooden frame, or lay them out on a clean towel. Putting the eggs directly in the refrigerator, still in their baskets or washer flats, is the simplest method.  The refrigerator will cool and dry them at the same time. Don’t be alarmed if some parts of the egg seem darker than others; the parts of the egg that are in contact with a flat or another egg will dry more slowly than the the exposed portions, and will look darker. This will vanish when the egg is completely dry.
9. Once the eggs are dry, pack them into egg cartons or flats.

5. Can I avoid using a chemical sanitizer?

The simplest method of egg washing is as follows, and it’s also sanitizer-free:

• Fill a metal bucket with 160 °F (70 C) water and the detergent of your choice (it should be food-grade, non-sudsing, and unscented. I like commercial dishwasher detergent.) This water is hot enough to badly scald you, so be careful.
• Slowly pour the water over a basket full of eggs, allowing the water to go down the drain.
• Don’t let the eggs stand in the water or they’ll cook (not to mention that allowing eggs to stand in water violates the rules of the USDA and many states).

That’s it. The water is hot enough to sanitize the eggshells without added chemicals. This method doesn’t work as well as one where the eggs are wiped, such as in the (using rotating brushes) or the watering-can technique (wiping by hand with paper towels), but it ought to be okay on eggs that are only lightly soiled. It’s certainly simple, provided you have an adequate supply of very hot water.

CAUTION: 160 °F water is hot enough to scald you, and splashing yourself is not an experience you’ll forget in a hurry.

6. What kinds of egg washers exist?

There are all kinds of commercial egg-cleaning machines, some quite enormous, washing eggs on an industrial scale. Other egg washers are quite small. And you can build your own small egg washer without much difficulty.

For wet-process egg cleaning, we can divide the field into immersion washers and spray washers. Immersion washers are cheap. Spray washers are better, but more expensive: they handle a lot more eggs per hour and get the eggs  cleaner. There’s also  dry egg cleaning, using something like sandpaper, which I’ll discuss later on.

I use an 1960s-era Aquamagic egg washer, shown below. Versions of this machine are still being manufactured, now called Sani-Touch. See my page for videos and more information.

I recommend that you start small in the egg business, which probably means that you should start with an immersion washer, or hand washing, or dry washing. Don’t go investing your retirement savings in a fancy washer yet.

Egg washing is a mature technology. The issues have been understood since the Thirties. However, early egg-washing machinery ran afoul of human nature. The old immersion-style washers worked superbly when run according to the instructions, especially if the water was dumped and replaced between each basket of eggs. But human nature is such that people can’t resist running “just one more basket” through the washer. Sanitizers are ineffective when used in dirty water, and eggs sanitized in dirty water spoil quickly.

This sort of thing has given egg-washing a bad reputation, even though egg washers that have none of these problems have been available for over fifty years, and proper egg-washing techniques have been well-known for over eighty years.

In the US, USDA-inspected eggs must be washed. In the EU, washing commercial eggs is forbidden. Go figure.

7. What should I know about immersion-type egg washers?

What’s an immersion egg washer? In its simplest form, an immersion washer is pretty much a bucket of warm soapy water that you lower a basket of eggs into, plus some means of agitating the water, such as by twirling the basket or sloshing it gently up and down by hand.

A standard five-gallon galvanized bucket is slightly larger than a standard egg basket, so you can give this a try at almost no expense.

This actually works pretty well, and you should think twice before doing anything much more expensive and elaborate.

The next step in terms of fanciness is to add some kind of agitation to replace the hand-sloshing step. This often takes the form of a perforated tube at the bottom of the bucket, hooked up to an air compressor. The bubbles keep everything moving, as shown in this video:

Fancier immersion washers don’t really work any better than this, but they can cost over $1,500. I once owned a like the one pictured here. I didn’t like it. I found it much harder to use than the “bucket and bubbler” method, and it was about 50 times more expensive.

Some immersion washers have water heating elements, but I think this is a problem, not a feature. If you have more than a few dozen eggs to wash, you can’t wait for the water to heat up in the bucket: you need to dump the dirty water and replace it with water that’s already hot. Time is money. And an ordinary household water heater is perfect for this job, so where’s the problem? But without plenty of hot water, you’ll be reluctant to dump the bucket as soon as you should, and your eggs will go bad in your customers’ refrigerators.

The USDA does not allow immersion washers for eggs under their inspection. Last time I checked, different states had different rules for non-USDA-inspected producers. My State, Oregon, does not allow the use of immersion washers under any circumstances.

Where immersion washing is allowed, do yourself a favor and add a final sanitizing step, where you spray a sanitizing solution over the eggs after you pull the egg basket out of the wash water. A large plastic watering can with hot water and chlorine at 100-200 ppm works fine for this. Sprinkle liberal amounts over the eggs in the basket.

Of course, immersion washers leave the eggs wet. Don’t pack them into cartons until they’re dry, or they’ll stick. But immersion washing leaves the eggs quite warm, and they’ll dry pretty quickly, even in the basket, but with small damp patches where the eggs touch each other. My favorite method is to simply put the wet basket in the refrigerator and pack the eggs into cartons later, when they’re dry.

In any event, you don’t have to use immersion washers. The method I give later on for hand-washing eggs works better than immersion washers, and doesn’t violate any USDA rules. It’s suitable for kitchen-sink egg-washing.

8. What should I know about spray-type egg washers?

The spray-type egg washers don’t immerse the eggs. Instead, they use a water spray that runs down the drain. This “total-loss” system prevents the bacteria from a contaminated egg from contaminating other eggs. The water spray is generally warm water with detergent and a sanitizer.

Spray-type washers almost always use rotating brushes as well, making them a lot like a car wash for eggs. The eggs come out dry, ready to be packet onto egg flats or into egg cartons immediately. This simplifies the whole process.

The best way of washing eggs is with an  candler-washer-dryer-grader machine. Everyone I know with a farm flock bigger than 200 hens either considers these machines indispensable, or lusts after one. These are expensive, with simple washer/dryer models starting at around $6,000 new, but they have been in continuous production for around 50 years, so old ones can sometimes be found for between $1,000 and $2,000 by putting an ad in you regional farm newspaper. Beware, though, that such units are often decrepit. The machines are complex and are hard to figure out if more than one thing is broken.

10. How can I clean eggs without making them wet?

Dry cleaning. Washing eggs in water is a lot more complicated than dry cleaning with abrasives. You can clean up lightly soiled eggs with various abrasives. Sanding sponges from 3M and others are good, and can be found in any hardware store. Loofas are also good. Some people use sandpaper or steel wool, but these aren’t as good as the first two.

Basically, you rub the egg until it’s clean, or you give up, or it breaks in your hand. This happens more often than you’d think, because dirty eggs are often cracked as well.

Dry cleaning doesn’t work very well to clean up eggs that have been smeared with the white or yolk of broken eggs in the nest.

Whatever tools you use to clean the eggs, wash and sanitize them from time to time.  Clean loofas or sanding sponges in soap and water, sanitize them in water with a little bit of bleach, then allow to dry.

These methods of cleaning are slow and tedious. They are suitable for small flocks, but when you have significant numbers of eggs to sell, the labor involved in cleaning the dirty ones can become a big barrier to success and satisfaction. If you want to have a small commercial flock on your farm, you will almost certainly want to look into wet cleaning.

11. What about mechanical dry-process egg washing machines?

Various dry-process egg-cleaning machines have been made, using sandpaper to scour the eggs. These have a tendency to turn the manure adhering to the eggs into a cloud of fine powder, which I wouldn’t breathe if I were you! I’ve never used one of these machines.

12. How do I prevent dirty eggs?

It’s typical for about 30% of your eggs to be dirty when collected. Washing eggs is tedious, so it helps if you prevent as many dirty eggs as possible.  Ways to reduce dirty eggs include:

• Prevent hens from sleeping in the nest boxes. Chickens want to sleep at the highest point available, so you can save yourself trouble by installing roosts that are quite a bit higher than your nest boxes. Once you’ve dealt with that, hens who stay in the nest box at night are probably broody.  They should be kept in a broody coop (a cage with a wire floor) for three or four days.  A broody coop is so unlike a nest that it tends to cure them of broodiness in three or four days. Give them food and water or they’ll go into a molt.
• Prevent hens from entering the nests with muddy feet. This is especially troublesome for hens with outdoor access.  If there’s a broad stretch of litter (straw or wood shavings) on the floor between the henhouse door and the nest boxes, their feet will be less muddy. Also, if you arrange it so they have to walk across a shallow tray filled with powdered gypsum, powdered limestone (not hydrated lime or quicklime — those are caustic!) or diatomaceous earth before entering the nest boxes, their feet will get coated with powder and won’t leave marks on the eggs. Replacing the perches on the nest boxes with trays about four inches wide will work.
• Prevent broken Eggs. Nests with insufficient nest litter or with too many hens jammed in at once will have broken eggs. These eggs are not only a total loss in themselves, but add a messy, hard-to-clean coating on other eggs.  I think that nests that are unusually wide and have unusually deep litter work very well.  I removed half of the partitions from a pair of 8′ nest boxes, leaving them with holes two feet wide instead of one foot wide, and this worked very well.  If the front boards on nest boxes are 6-8″ high instead of the traditional 4″ high, you can pile in a lot more litter.  If you use relatively heavy litter such as straw or wood chips, the hens don’t scratch it all out of the box as quickly as wood shavings.
• Reduce traffic. Every time a hen enters the nest box or moves around while inside, there’s a chance of an egg breaking.  Darkening the nests makes the hens less active. Turning the nest boxes around to face the wall or darkening the front with flaps of plastic tarp work well. Using community nests or tunnel nests also works. Finally, roll-out nests allow the eggs to roll into a collection area away from the hens.

More Resources

• from ATTRA.
• . Egg washing is covered on pages 6-7. The other sections are also worth reading.

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