A Japanese chef told me that I should always chill tempura batter to ensure it remains light, crisp and fluffy after it is cooked. How does chilling achieve this?

Tom Dressler, Amarillo, Texas, US

If I open a big tub of yogurt, eat from it, and put it back in the fridge. When I open the tub the next morning for some more yogurt, there is a layer of water / watery yogurt floating on top of the tub. I'm told all I need to do is 'stir' the water back in, but why does this happen?

Also, why does the yogurt not go watery before I open the tub? If I keep the tub in my fridge for a week before opening it, the first time I open it the yogurt is fine.

Lastely, is there a way to prevent the yogurt from going watery? I find it rather off putting.

I have recently been living in Guyana's rainforest, and have consumed a large number of magoes. Now, I always assumed that a ripe mango would contain more calories than a green one. They certainly taste a lot sweeter. Is this actually the case? And i so, how does the mago aquire this additional energy if they are picked whilst still green and allowed to ripen afterwards?

Fish, either from fresh or salty water, tastes “fishy”. So do lobsters, crabs, clams, crayfish, and frog’s legs. Some aquatic vegetation, such as seaweed, also tastes fishy. What is the source of this fishy taste, and why do so many different aquatic foods have it?

Sally Manders, London, UK

If I eat spicy food such as a hot curry or a dish with chilli, I consistently get hiccups. Many people get hiccups after consuming carbonated drinks.

Why are some foods more likely to cause hiccups? How is digestion linked with this involuntary contraction of the diaphragm?

Richard Fisher, London, UK

I made a salad dressing with olive oil, apple cider vinegar, garlic cloves chopped into halves, fresh ginger, mixed herbs and mustard powder. When the dressing was finished I put a lidded jar of it in the fridge, and two days later topped it up again with fresh ingredients.

The following day the garlic from the original batch had turned bright blue. Why?

Ellice Bourke, Katherine, Northern Territory, Australia

Of all the vegetables I buy, whole iceberg lettuces have the greatest longevity. They are edible up to three weeks after their "best before" date. Other vegetables succumb sooner.

Why does it last so long compared with, say, tomatoes, broccoli or radishes?

Finn de Boer, Rotterdam, the Netherlands