• Chefs share their scrambled egg secrets
• Put an egg on it: poached, fried and boiled egg recipes

Since 2010, Richard Cornish has been helping solve readers' culinary conundrums, while slipping in some appalling single entendres and questionable humour with a little food science. Here are some of the most common egg problems and how to fix them.

Boiled eggs

How long does it take to boil an egg? J. Hosking

While in Spain working on a cookbook, I took photos of some dishes that were topped with hard-boiled eggs. When I looked back at the images I saw an ugly grey ring around the yolks. In Europe they have some nasty strains of salmonella and chefs are no longer allowed to make raw egg dishes and overcook their eggs just to be safe.

How long to cook an egg will depend on the temperature of the eggs and water as well as the size of the egg and the volume of water. The bigger the egg, the longer it takes.

The very runny and rather delicious oeuf a la coque, in which the white is creamy and the yolk is just warm (just right for dunking toast soldiers), takes three minutes when a 60-gram egg is plunged into two litres of boiling water. Boil for two minutes longer and you have a coddled egg. Boil for another minute and refresh in cold water and you have mollet eggs. This is an egg with a creamy soft yolk but the white set enough so the egg can be peeled and the yolk won't run – perfect to top salad with anchovies. Boil for 10 minutes in total and refresh in cold water and the egg will be hard-boiled but the yolk creamy, not crumbly.

I was slicing boiled eggs to make curried devilled egg and the knife was crushing the eggs and smearing yolk across the white. M. Broughm

I am thrilled to see such a wonderful culinary tradition being kept alive. The union of Keen's Curry Powder and boiled egg has been the foundation canape for a thousand country wedding receptions and the olfactory flashpoint for millions of family road trips up the Newell Highway. (Rule one – never eat curried egg on a hot day in a station wagon bound for the Sunshine Coast.)

Devilled eggs require the careful slicing of a hard-boiled egg lengthways to reveal the yolk inside and create the perfect cradle of rubbery white to deliver the mashed yolk, mayo and curry powder to the lips. To stop the eggs smearing, wipe the knife with a damp cloth before cutting each egg. This lubricates the blade and wipes the egg yolk off from the previous cut. If you have a bread knife with a serrated edge, use this, as it is perfect for slicing tomatoes, ripe fruit and hard-boiled eggs. If not, make sure your knife is sharp and draw the blade across the surface of the egg without too much pressure. Best served with Australian lager or Ben Ean moselle.

In regards to slicing a hard-boiled egg, several readers, including chef Victor Liong of Melbourne's Lee Ho Fook, suggested tying a piece of cotton, dental floss or fine fishing line to an immovable object, making the line taut, then pulling this down through the boiled egg to slice it.

Why is it sometimes impossible to peel a boiled egg cleanly and other times the shell comes away perfectly? A. Ries

It's all about freshness. And perhaps not in the way you think. Egg whites change from being slightly acidic when freshly laid, to more neutral as they get older. In freshly laid eggs this acidity makes the egg white attracted to the membrane lining the eggshell. This means that when you boil a fresh egg the membrane, or skin, cooks onto it so when you peel off the shell and membrane, bits of egg white go with it. As the egg ages the pH rises, or becomes less acidic, and the albumen becomes less likely to stick to the membrane. So if you want perfect peeled boiled eggs, use them a bit older. You can artificially raise the pH by adding a little baking soda to the water in which you boil fresh eggs, but beware this can exacerbate the egg smell.

How do I peel the perfect hard-boiled egg? W. Fleming

As soon as the weather warms this perennial question returns in a flurry. On The Kitchen Cabinet on BBC Radio 4, Jay Rayner spent a good deal of time discussing this with four experts. Each presented a different method. One said the eggs must be at least a week old – not a problem if you're buying from an Australian supermarket. Another said that if the water was slightly acidulated or slightly alkaline then shells would come off more easily. A scientist said that it is simply a matter of getting between the membrane on the shell and the solid white, which one does by finding the air pocket under the shell, generally but not always under the wide end of the egg. One then peels from here. A fourth expert maintained that plunging cooked eggs into cold water ensured that shell could be peeled away without damaging the egg. A survey of listeners found this to be the most reliable method.

What is that grey ring around the yolks of boiled eggs? N. Barling

I remember working with a photographer in Spain and he was taking these beautiful shots of a dish made with hard-boiled eggs smothered in aioli. The only trouble was, the yolks were greenish and surrounded by a grey ring. In Europe they have different, more aggressive types of salmonella and cook the bejesus out of all their eggs. It's amazing what Photoshop can fix. When you cook eggs for long times, sulphur from the white comes into contact with iron from the yolk, creating ferrous sulphide. This reaction occurs more rapidly in older eggs, as the whites have become more alkaline and this helps the reaction. Reader H. Oates once advised that the grey ring in hard-boiled eggs could be avoided by putting them in cold water straight after cooking.

Raw eggs

I was told by a friend not to separate eggs using the shell. She couldn't explain why but said it was dangerous. P. Taggerty

If you're separating eggs for making a raw egg dish such as mayonnaise, remember that eggshells can be contaminated by salmonella bacteria. By separating the yolk from the albumen using the shell, you're bringing a nutrient-rich food source in direct contact with the salmonella. Leave the mayonnaise above 5C for more than a few hours and you're going to be sending customers, friends or relatives to the emergency department. Food poisoning generally happens after a series of interconnected small problems. The Australian Food Safety Information Council recommends that cooks invest in an egg separator.

I want to make mayonnaise, but I am worried about using raw egg yolk because of salmonella. K. Puteri

I make raw egg yolk mayo at home and have never had a problem. Yet. Salmonella is ever-present in the poultry industry globally. There is a nasty type of salmonella called enteritidis that gets inside the egg. Thankfully, it hasn't been detected in Australia since testing began in 1996. Because of it, raw egg dishes have been banned in other countries. In Spain, where mayonnaise is integral to many dishes, many restaurants use milk as the emulsifier. About 100 millilitres of very cold milk is blended in a food processor with a small squeeze of lemon juice, a small clove of garlic and little white pepper and a pinch of salt. Added to this very slowly, with the blender still running, is about 190 millilitres of vegetable oil, a few drops at a time until it starts to thicken. This makes a paler, lighter tasting mayo that can be stored in the fridge for a few days. However, it is not nearly as tasty as raw egg mayo. In Australia, the risk from salmonella in eggs comes from salmonella bacteria in the poo on the outside of dirty eggs. Because of this the egg industry washes the eggs. If you have backyard hens, wash the eggs in very warm water before you use them in raw dishes such as mayo.

I have always let my children lick the bowl after making a cake. Now I just read on a packet mix, "Do not eat the cake batter; it contains raw egg". Elsa Z

The Victorian Government Better Health Channel website recommends that one avoid food containing raw egg, including homemade mayonnaise, and raw biscuit dough and cake batter. Eggs can be contaminated with salmonella, leading to food poisoning. It would be irresponsible for me to make comments such as "tell the fun police to shove it up their fundament". Instead, I can offer some extra information. The website also states that the other factors that increase the risk of food poisoning are time and temperature. Salmonella bacteria need warm conditions – above 5 degrees and below 60 degrees – for several hours to multiply. There is a greater risk of food poisoning from eating raw cake batter left out at room temperature. I'll leave it to you.

Poached eggs

What is the secret to good poached eggs? P. Nevin

Depends on how you like them. If you like them hard and tasting like salt and vinegar chips, drop the eggs into a big pot of simmering water that has been heavily salted and acidulated with lots of white vinegar and swirling like a whirlpool. They'll be just like the eggs in every inner-city cafe in the late 1980s. Put on some Sade and it will be like time travelling. To move forward to 1990, sprinkle them with dukkah. Eat your heart out, Timelords. Seriously, take really fresh eggs as the whites will be intact. Put a small heatproof plate in a medium pot and cover with 10cm of water and lightly season water with salt. Bring water to 80C (use a thermometer). Crack the eggs into a cup, then slide them into the water and poach for four minutes. Remove. Season. You should have a translucent but set white wrapped around a slightly thickened but still runny yolk.

How do I get beautiful poached eggs like the ones in my cafe? L. Bowman

There are some household jobs that are best left to experts. Animal surgery, in-ground pool electrical work and poaching perfect eggs. This is a job for the professionals. All egg whites, no matter how fresh, have thicker, more viscous parts and thinner, runnier parts. The runnier part of the egg white dissipates quickly in hot water, setting into a white shroud that looks like a pale Harry Potter Dementor haunting the yolk. You can strain this away before you poach the egg by cracking the egg into a fine mesh sieve then sliding the yolk and thicker part of the white into swirling, gently simmering salted water. The vortex in the water helps the egg white form a pleasing globe. The idea of acidulating water by adding a dash of vinegar does have some scientific basis – the acid denatures the protein. But in doing so it tends to overset the egg as it cooks.

How do I make poached eggs that look like mozzarella balls? P. Arcuri

Can't we just be happy with simple old-fashioned, flat poached eggs? You are, of course, referring to the spherical poached eggs seen at fashionable cafes. They're made by lining a small bowl with a sheet of plastic film, brushing it with oil, adding a knob of butter, cracking in an egg, seasoning with salt and pepper, then gathering up the edges and tying in a tight knot. Gently place this into a large saucepan of water, preheated to 85C, lined with a heatproof plate. Cook for 12 minutes.

Scrambled eggs

How do I stop scrambled eggs from going rubbery? L. Gammage

Time. It's an ingredient often lacking in cooking. I was told of a family who would microwave their "roast" chicken because it was quicker. They did this so they had time to watch the football. When I heard this I had a vision of a factory farm with humans eating pelletised food from a trough watching an endless loop of Australia's Got Talent. Enough dystopia. Take your time. The lower the heat they are cooked over and the slower you stir the eggs the lighter and smoother they will be. As they are heated the protein in the egg whites forms a net-like structure that holds in moisture. If you hit the protein with too much heat too quickly they coil up and squeeze out the moisture and you end up with scrambled eggs like the ones at that dodgy school camp in year 7 – chewy egg lumps sitting in water. Heston Blumenthal has a recipe for eggs that requires seven eggs, 25 millilitres of milk, 20 millilitres of cream, 20 grams butter and a pinch of salt. These are gently mixed together in a bowl and then cooked in a double boiler over simmering water and gently stirred with a spatula for 15-20 minutes. It is delicious, but it takes time.

Why are my scrambled eggs watery? D. White

There is no need to be embarrassed about your watery scrambled eggs. It happens to the best of us at times. You need to relax and slow down. Take your eggs, gently beat them with a fork. Add a tablespoon or so of milk to the eggs. Melt some butter in a pan over a low heat. Allow to bubble. Pour in the eggs. Move about with a rubber spatula. When the eggs are set but still glossy remove from heat, serve and season. If you cook your eggs too fast the proteins in the albumen tighten up into little coils and squeeze the liquid out of the eggs as opposed to holding it all together like a solid custard. Cook low and slow and you'll never have watery scrambled eggs again.

How do I make fluffy scrambled eggs? L. Franks

Steam power. Steam is what makes pastry puff, sponge cakes spongy and scrambled eggs fluffy. When you heat liquid the water evaporates and expands. If that steam is surrounded by dough, batter or egg albumen it creates holes as it pushes its way out. These are the little pockets in puff pastry, the holes in a sponge and the fluffiness in eggs. If you add a tablespoon of liquid of extra liquid to eggs and give them a good beating some of the trapped air will help form bubbles that set as the eggs harden with heat. And as the water bubbles into steam it creates little pockets in the eggs, thus creating fluffiness. If you add milk, the fat in it interferes with the egg proteins bonding, making creamier scrambled eggs. The ultimate in fluffiness occurs when you separate the eggs, whisk the whites, fold them back in the beaten yolks and gently fold that mixture through some hot butter in a pan. Remember to be gentle with your eggs, folding them with the spatula and never taking to them with a wooden spoon like a sadistic Dickensian poorhouse master.

How do cafes get their scrambled eggs so creamy? K. Whitehead

Cream. Cream and butter. Cream and butter and salt. Now if you are worried about your heart health, visit heartfoundation.org.au. But if you want to know how to make them, take six large eggs, the yolks of two eggs, ¾ teaspoon salt, 30 grams of chilled butter cut into little cubes and 30 millilitres of cream. In a bowl beat the eggs, yolks and salt for a minute then let it rest for 15 minutes. Add the butter, and pour the mixture into a medium nonstick pan. Cook over a medium-low heat, stirring continuously with a wooden spoon, until the butter melts and the eggsbegin to thicken and form curds. Remove from the heat and add the cream and stir until mixed well. Pile on to enough toast to feed four. See your doctor if pain persists. Reader C. Johnston offered that the secret to perfect creamy scrambled eggs was to stir them with a spurtle, a traditional Scottish wooden porridge stick.

A friend was telling me that she makes her scrambled eggs using her coffee machine. Is that possible? E. Van Hoeven

Yes, unfortunately it is possible to cook eggs using the steam from a domestic coffee machine. Not that you'd want to. Egg-white proteins ovotransferrin and ovalbumin start coagulating at 61C and 84C respectively, whereas the yolk starts thickening at 65.5C. Steam is 100C and 100 per cent overkill. At that temperature the proteins will set very tightly. As they set they will trap some air bubbles making them light but also some of the water from the steam. So you end up with aerated, rubbery eggs that ooze liquid as they cool. You can cook eggs anywhere the temperature reaches above 65C, such as inside the dishwasher, on a car engine block or the muffler on your lawn mower. A thick-based pan, however, is the best place. In it melt some butter over low heat, add lightly beaten eggs and cook slowly folding over the eggs as they set. Remove the eggs while they are still slightly wet as they will still cook due to the residual heat. Season.

When I was growing up my mother always told me to add salt to my scrambled eggs well before I put them in the pan. Why? M. Price

Families tell their young ones some of the oddest things. Mine spent a good deal of time trying to convince me I was an adopted piglet from a pig farm. I never believed them but didn't eat bacon until I was in my 20s. On this occasion, however, your mother is correct. As the proteins in the eggs are heated, they coagulate and pull together tighter. As they do they squeeze out moisture, making tough curds. Added salt prevents the proteins bonding too tightly. If you add salt, whisk it through and leave it for 15 minutes or so to allow the salt time to dissolve and help it stop the proteins from toughening up.

Fried eggs

I like my fried eggs runny but not too runny. E. Kidd

Put a lid on it. Literally. Frying delivers heat from the bottom of the pan and the fat stops the eggs from sticking while adding flavour. Placing a stainless steel lid over the eggs as they fry will reflect heat back down onto the eggs, trapping hot air and thus cooking them from above.

Assorted

My eggs keep freezing in the fridge. I would adjust the thermostat higher. Turns out my wife's yoghurt kept going off, so she would adjust the thermostat lower. How can we maintain a happy married life while keeping our refrigerated foods the way we want them? G. Goodyer

I know couples who have separate fridges. But that's another story. You'll note most eggs in the supermarket are not in the fridge. This is because moist air condenses on cold eggs and creates a good environment for bacteria. If they were stored in the supermarket fridge, moisture would condense on the way home. Australian Eggs, the egg peak marketing body in Australia, recommends that you store eggs in the middle of the fridge in the cardboard box which protects them from fridge aromas. Your fridge should be running at or below 4C but above 0C. Use a thermometer to make sure it is in this range. This temperature range will keep you and your wife happy. The least risk is to use the eggs directly from the fridge and by the use-by date. Growers and chefs say if you have clean, freshly laid eggs, keep them between 12C-16C and use them within a week.

I turned my fridge up high and accidentally froze my eggs. Can I still use them? S.J.F.

Yes you can but you want to get in quick. Freezing the eggs will probably have caused the membrane around the albumen and yolk to rupture. This will allow air and bacteria into the eggs where they could breed up. If the eggs have just thawed you'll be OK but if they have been sitting in the fridge for a few days ditch them.

How do I get my souffle to form a crown? C. Leskiv

Make a collar with baking paper. Make sure the souffle dish is well-buttered and the surface of the paper facing the souffle is also well-buttered. After the mixture has been poured in, run your finger around the rim between the batter and the dish. Remember, when making a souffle: preheat the oven; don't over-beat the egg whites; bake on the bottom rack in a conventional oven so the top doesn't dry out; and don't open the door during cooking.

Double yolkers

Is there a season for double yolk eggs? M. Villanti

For any of you who keep backyard chickens you will know that when the pullets first come into lay there is that lottery of how many yolks will be inside the shell. Will there be one or two, will the yolks be normal or the size of a marble? Shelley Green of Green Eggs in Great Western in Victoria says: "When they are younger many young hens may release multiple eggs. As chickens are being hatched throughout the year there is no one season for young birds entering the flock. However, many people who keep chickens tend to buy young birds in spring so may be aware of double yolk eggs at that time." You don't see double yolkers much in shops as they are mechanically removed during sorting and sold as farmgate seconds or used in industry. Double yolkers are perfect for omelettes and other breakfast dishes but don't use them in baking where the recipe calls for whole eggs. The ratio of yolk to white is significantly different and can affect the result.

If a recipe asks for six eggs can I use three double yolkers? B. Grech

Yes and no. If you're baking, then definitely no. For those who don't know, a double yolker is an egg, laid by a hen often at the beginning or end of her career, in which two yolks have been encapsulated. Let's say that in a 60-gram egg you're getting roughly one third yolk and two thirds white. In a double yolker you're getting twice the yolk but around the same amount of albumen. In a cake recipe, where you're using the egg to help hydrate the flour, if you substitute half the number of double yolkers you're going to end up with a dry cake. Double yolkers are perfect fried, scrambled or boiled and beaten to dip food in before crumbing.

Beyond hen's eggs

Can I cook with emu eggs? V. Caruthers

In Victoria Heywood's book Possum Pie, Beetroot Beer and Lamingtons, there is a recipe for emu-egg sponge. It appears above a recipe for stuffed, baked possum. It reads to take one emu egg, crack it into a bowl then whisk it for five minutes; then whisk in a cup and a half of sugar for 15 minutes until light and foamy. Then sift two teaspoons of baking powder into two cups of plain flour and fold this into the foamed eggs. Then add one cup of boiling water in which a tablespoon of butter has been melted. Pour the mix into two well-greased large sandwich tins and "bake in a quick oven". Melbourne chef Shannon Bennett has made emu-egg sponges at the Piggery Cafe at Burnham Beeches in the Dandenong Ranges. His recipe makes three 20-centimetre sponge cakes and he says one 500-gram emu egg is equivalent to 14 large hen's eggs. That would make scrambled eggs for about six. If planning to cook with emu eggs please procure them from a specialist vendor and do not steal from nests in the wild. Emus can run faster than 60km/h and have talon-like claws – think velociraptor with a quizzical expression.

Can I use duck eggs to make mayonnaise? L. Chan

Yes. It will be richer tasting and will split faster than chook eggs. For one duck egg yolk add the juice of half a lemon, one teaspoon Dijon mustard, a good pinch of salt then mix. Slowly whisk in three-quarters of a cup of delicate extra virgin olive a few drops at a time to begin with, whisking until it emulsifies.

I always find my boiled quail eggs get torn or damaged when I try to peel them with my old fingers. Is there an easier way? J.Driscoll

I love a good quail egg. They can make rich punctuation to a summer salad or a diminutive sunny-side decoration to a fried puck of black pudding. Egg shells are mostly calcium carbonate. This is a compound that dissolves easily in acid. Take your boiled eggs, allow them to cool. Soak them in cheap white wine vinegar. The acid will dissolve the calcium carbonate, at the same time releasing little bubbles of carbon dioxide. Do this for 10 minutes or so or until the shells soften enough to peel off in a single piece. Rinse in cold water. Pat dry. Enjoy.

Brain Food by Richard Cornish is out now from MUP (RRP $19.99, eBook $11.99).