Category: Science

Tá Éire go breá

Well, then. Hello!

I’m still in Ireland, having been analysing my electroencephalogram data for the past two weeks with the help of a collaborator, so I’m sorry for the protracted blogular silence. Far too busy to write decent blog posts, and I can’t really bake things in a hotel room when I get back from analysing data every day, unless I tear up the floorboards and get a fire going with them and wrap bakeable things in aluminium foil and cook them in the embers. It’s good weather outside for making a sorbet or something, though.

So just a quick update for now, and it wouldn’t be The Island of Dr Gâteau without some baking and some science. So here’s the baking, not done by myself, as you may be able to ascertain from various subtle clues:

(Macarons from the Ladurée boutique in the Brown Thomas department store here in Dublin – bitter chocolate, orange blossom, fig and date, violet and blackcurrant, red fruit, and pistachio.)

As for the science…

Maybe this is just me (and 90% of the people I know) but are you familiar with the whole “dessert stomach” phenomenon? You know, you eat an enormous meal, you feel like your stomach is about to split into shreds of over-strained, tormented muscle, yet when someone mentions the possibility of dessert, somehow you discover that you’d be quite able to eat dessert, possibly a large amount of it, regardless of your previous extreme satiety. It’s as if you’ve got an extra stomach off to the side that’s reserved specifically for dessert.

Or like how I just ate an enormous bowl of bibimbap and feel thoroughly full, yet I’m actively considering going out and getting a crêpe stuffed with Belgian chocolate and strawberries. Whyyyyy?

This is a pretty well-studied phenomenon (not just by myself in an unofficial capacity after many meals), with it being repeatedly demonstrated that variety definitely influences habituation to food. That is, you get sick of a particular type of food during a meal, but if a different type is introduced, you can eat more than you would have if it was just the one original type of food.

But how similar or different do foods have to be for a person to be able to continue eating after they’ve habituated to one type of food? If variety influences habituation, what is “variety”? If I give you a bowl of macaroni and cheese made with elbow pasta and you eat as much as you can, then I give you a bowl of macaroni and cheese made with spiral pasta, is that sufficiently different for you to be able to keep on eating a bit more? Or do I need to give you chicken nuggets to make it different enough from spiral macaroni and cheese so that you can keep eating?

In an amazing and remarkable act of extra-special good fortune, research can answer exactly those questions. Exactly. And guess what? Spiral macaroni and cheese is different enough from elbow macaroni and cheese for someone to keep eating it after they’re sick of the elbow stuff.

One suggestion as to what’s happening in the brain at this point is that a different part of your memory is being activated by the new food if it’s sufficiently different from the previous food. A particular set of neurons responds to the first type of food as you consume it, and these neurons allow for the emotional and sensory aspects of the food to be processed (so, how much you enjoy it, what the flavour and texture are like, etc).

However, over time, these neurons become less and less active because they can only be really active for so long, and this results in the habituation – you get sick of the food, and those neurons can’t go back to a state of high activity until they’ve recovered (for maybe at least a few hours). But a new food that’s adequately different from the first food – that activates a different set of memory neurons, and the whole process can start again. Not from scratch, obviously, since you’re not going to eat forever just because your pasta is now a slightly different shape again – your brain is still getting feedback about how much food you’ve eaten and how full you are (which it assesses by getting information about hormone levels, and from nerves relaying information about how stretched the stomach is, and so on).

So there you go. I was quite surprised at how little variety or difference is required for someone to keep eating despite having previously habituated to a food. I usually have to at least change from a savoury food to a sweet one. And of course, it has pretty interesting implications for unhealthy eating habits such as over-eating the wrong kinds of food. So comparing spiral macaroni to elbow macaroni – it has important health implications. You go tell people that.

Anyway then, I’m dreadfully sorry for not commenting on all the blogs I usually do – if I’m a frequent visitor of yours, rest assured that I’m reading what I can, and I’ll be back to commenting fervently and admiringly in a few weeks or so. Until then, I’m afraid the fair Emerald Isle beckons, and I’m off to London next week which should be delightfully hectic and fun. In the mean time, if you’re in the mood for a festive drink and quite fancied the butter beer I posted a while back, take a look at the Buttered Beere post at 12 Bottle Bar – David has done an absolutely phenomenal job of properly contextualising and researching the drink, including getting some highly illuminating information from a professor of food history on all of those historical measurements that I had no idea where to even start with when I tried to make the buttered beer recipe out of the Huswifes Handmaide. Amazing.

In lieu of a recipe, following are a few photos from my Irish travels so far.

Happy holidays!

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6 Comments by on December 18, 2010
filed in Science, Site admin
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Peking Dux cupcakes


When I am in conversation with respected dignitaries and important diplomats and they ask me, “Jessica, what would you say your motto is when it comes to baking?”, I usually recite what has become a critical and apropos phrase for me: “I do not take requests – I accept challenges.”

And challenges they must be, or I cannot quite find the motivation to give a damn. Someone recently made a request for me to try making white chocolate cake with raspberries (try, as if I hadn’t done it dozens of times before and as if it would be an attempt that might fail because it was just too overwhelming and complicated), or a hummingbird cake. I struggled not to fall asleep during that request. Maybe if the hummingbird cake was a hummingbird cake because it was made out of hummingbirds… no, too gruesome, but maybe if I had to collect fresh nectar from plants and make that into a cake? Now that’s a challenge that I would consider accepting and be motivated to achieve. Actually, let me write that down in my notebook in case I want to eventually challenge myself to it.

The brain is interesting (you should expect this by now) when it comes to being motivated to achieve a goal or rise to a challenge. Apparently I don’t even need to be consciously aware of a baking challenge in order to be motivated and to try to improve my performance – research has found that subliminal incentives are enough to make people try harder to achieve a goal. And my entire brain doesn’t even need to be involved. Just half of it.

The study got people to squeeze a hand-grip as hard as they could (the hand-grip can measure how hard the participant squeezes it), and motivated them to do so by offering them money. The amount of money varied, and the harder the participant squeezed the hand-grip, the greater percentage of that money that would get. So, the idea was that they would be more motivated to squeeze the hand-grip harder when the amount of money on offer was greater so that they would get a bigger pay-off.

But the thing was, the participants weren’t consciously aware of the different amounts of money on offer in each trial, because the amount was indicated by an image of coins that was flashed up subliminally – too quickly for the participant to consciously be aware of. Not only that, the image was only presented to either the left half or the right half of the brain. This was done by only presenting the image in the left half of the visual field (information from which is processed by the right hemisphere of the brain) or the right half of the visual field (information from which is processed by the left hemisphere).

Participants did squeeze the hand-grip harder on trials where the coin image told them that larger amounts of money were on offer. Also, they only did this when the image was presented to the brain hemisphere that was also in control of the hand that was squeezing the hand-grip. So if the subliminal image popped up in the left visual field, which feeds into the right hemisphere, which controls motor actions on the left side of the body, and the hand-grip was in the left hand, the participant squeezed harder on trials involving more money. But if the image was presented to the left visual field, which feeds into the right hemisphere, which controls motor actions on the left side of the body, but the hand-grip was in the right hand, which is controlled by the left hemisphere – no effect of the amount of money on motivation to squeeze harder.

So obviously the upshot of this is that you can challenge me subliminally using pictures of, say, blue cheese and an empty muffin pan, but if you present that to my left visual field… I’ll… only make the recipe… with my right hand? Whatever the case, motivation can occur within one half of the brain and one half of the body, seemingly independent of the other halves, which I think is pretty cool.

And I was challenged (in quite a superliminal way, really) over dinner one Friday night to make Peking duck cupcakes, by someone who comprehends what constitutes a challenge for me, and so I was motivated to rise to this challege. And these cupcakes were named Peking Dux cupcakes in honour of he who created the initial concept of them through this very challenge.

After the challenge was issued and some research revealed to me that Peking duck makes a good flavour-pairing with bourbon whiskey (and it does, oh it does – the combination is almost like fruitcake somehow, sweet and rich, and the cupcakes were a runaway success enjoyed by all), it was a crazy downhill ride from there. And as I step off my toboggan of learning, I bring you this message: bacon isn’t the only meat you can put in a dessert. And this is a message I intend to re-emphasise in the near future. Until then…

Read on for the recipe for Peking Dux cupcakes (Peking duck & bourbon cupcakes).

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18 Comments by on November 14, 2010
filed in Baking, Science, Sweet
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Delusional idiots, choice blindness & jam


I love how stupid the brain can be. The way it’s wired can often result in some pretty stupid behaviour in, say, the human possessing the brain. And I love it. I find it entertaining, in a bizarre and somewhat despairing way, and I find it informative, because it tells us about the elaborate, multi-coloured, lumpy-textured blanket of self-serving sham and deception that our brains crochet for us to protect our precious egos and make us think we’re, like, totally awesome ‘n’ stuff and so much better than, I don’t know, that random guy over there – just look at that idiot. He thinks he’s so good, but he’s not. But I am. Seriously. You probably don’t even know how good I am, because you’re probably an idiot too. Poor, stupid idiot.

My favourite example is the better-than-average effect, a convenient self-serving cognitive bias that means that a lot of people think they’re, hmm, better than average. A lot of people, as in 80% of the population… which is interesting when, by definition, only 50% of people can be better than average. So for things like sense of humour, or driving ability, 80% of the population thinks they’re better than at least 50% of the population. Awesome, well done on the mathematics there.

An extension of the better-than-average effect is the Dunning-Kruger effect, which makes me want to laugh until I vomit in disgust or something, because it is bitterly funny and depressingly amazing. The Dunning-Kruger effect describes the tendency for incompetent, unskilled people (i.e. the worse-than-average people on a given task or skill) to completely overestimate their ability. So now it’s not just people thinking they’re kind of more awesome than the majority – it’s the certified idiots thinking they’re great. The effect is perfectly summed up in the title of the original paper by Dunning and Kruger, “Unskilled and unaware of it: how difficulties in recognizing one’s own incompetence lead to inflated self-assessments”. There was also another chap who put it quite nicely, more than a century before:

“Ignorance more frequently begets confidence than does knowledge.”
-Charles Darwin

(And following on from that, another twist in the story is that competent, skilled people are also unaware of their competence or skill – but they tend to underestimate it. So, basically, we’re mostly kind of useless at judging the difficulty of tasks and at assessing our own competence when it comes to said tasks. There are people who are good at those judgement calls though – people with depression. Sigh.)

So our brains like to protect us from realising how incompetent or inaccurate we are, which isn’t surprising, because if you spent your life not being confident that your judgement in general was at least “adequate”, if not “amazingly blindingly fantastic and infallible”, you’d be crippled by self-doubt and unable to make decisions. Consequently, our brains have become pretty good at telling us “Oh hey, you know that decision you made? Brilliant. Well done, you. No doubt you made the right choice there. Help yourself to some ice-cream or something.”

For instance, you give me two photos to look at briefly:

I have to choose which one I think is more attractive:

Then, in a sleight of hand, you swap the photos without me knowing, and give me the one I didn’t choose:

And you ask me to explain why I chose that one. And I’ll do a fantastic job of explaining, and I won’t have noticed it wasn’t the one I originally chose. This is called choice blindness, and the theory is that I don’t realise there’s been a deception and a swap but I think that I must’ve chosen that particular photo for a reason, so my brain does a fantastic job of retrospectively justifying that “choice” because, hey now, I wouldn’t make a bad choice. Not me. Oh no.

Kind of unsurprisingly, this extends into the realm of taste, flavour and food. In an experiment by Hall and colleagues, participants had to make a choice between two types of jam or two types of flavoured tea. The bit of the experiment that thrills me no end is the way the sleight-of-hand was conducted – jars with secret compartments. Ah, brilliant!

So in one instance of the experiment, there would be two jars and the participant would take a spoonful of jam from an opaque white plastic jar (and maybe it was cinnamon-apple jam) and taste it, and the experimenter would ask the participant to rate how they liked the jam on a scale of 1 to 10. While the experimenter was distracting the participant by asking for the rating, another experimenter surreptitiously turned the jar upside-down. Then the participant tasted a sample from an opaque blue jar, this time containing a different jam (maybe grapefruit). Again the participant was asked to rate how they liked the jam, and again the other experimenter turned the jar upside-down without the participant noticing. And the marvellous thing is that the jars contain two compartments, so when you turn them upside-down and take a sample of jam, you’re getting the other jam – turn the cinnamon-apple jam jar upside down and you get a jam that looks identical, but is actually the grapefruit jam. Turn the grapefruit jam jar upside down and you’ll get the cinnamon-apple jam. Gah! So cunning!

So the participant was then asked to re-sample the jar that they had given the higher rating to out of the pair. Say they rated the cinnamon-apple jam higher. The cinnamon-apple jam jar has now been turned over, and the participant takes a sample of jam (which is now grapefruit jam) from the same jar and tastes it, and now… they’re asked to explain why they preferred that jam to the other one.

And they do explain.

And they generally haven’t noticed that the jam has changed.

In fact, in two-thirds of these jam-tastings, the participants didn’t realise the jam had been changed.

It was the same case when the participants sniffed the flavoured teas. They’re less likely to detect the change when the two samples are somewhat similar (e.g. blackcurrant jam vs blueberry jam) but even when the difference seems like it would be obvious (e.g. cinnamon-apple jam vs grapefruit jam, or aniseed-flavoured tea vs mango-flavoured tea), more than half the time the change was not detected.

In the case of the cinnamon-apple jam vs grapefruit jam, just over 20% of people immediately noticed that the jam had been changed and that they had been given the jam that they hadn’t originally preferred. Another 20% reported, when asked, that some quality of the jam they had preferred had tasted different the second time, so maybe it was a bit stronger or a bit sweeter, but they still didn’t notice the change. And less than 10% said “Hey… umm… was that a different jam?” or something along those lines towards the end of the experiment, well after the change had occurred. For apple pie-flavoured tea vs honey-flavoured tea, the change was only detected immediately about 7% of the time, it was detected retrospectively about 7% of the time, and no other change in the qualities of the tea was reported. So the change went completely undetected 86% of the time. The change between ginger jam and lime jam went completely undetected about 63% of the time. The change between blackcurrant jam and blueberry jam went completely undetected about 80% of the time. Seems kind of unbelievable, doesn’t it?

It’s not that the flavours were difficult to distinguish: another part of the experiment showed that participants had no trouble telling apart the different jam or tea flavours. Participants were often very surprised or voiced disbelief when they were told that the samples had been switched – they genuinely (unless they are very good actors with strange motivations) did not notice the change.

And in addition to this experiment being dastardly and clever (everything you want in an experimental psychology study), the authors are people I want to hang out with, because they made this paper fun to read with its rhetorical questions and random embellishments. I’ll leave it to them to outline the limits of the insight with which this experiment provides us:

Obviously, an experimental finding like choice blindness is bound at the limits by choices we know to be of great importance in everyday life. While it lies close at hand to speculate about couples at the altar solemnly affirming their choice of partner, and then (after the minister pulls some unearthly sleight-of-hand!) bringing home a complete stranger, no one would fail to notice such a change (and this, we hope, includes even those involved in the most hasty of Las Vegas marriages).

So true, Hall et al. (2010), so true.

In my own clunky attempt at sleight-of-hand, I’ve created what I consider a nose-bleedingly amazing triumph: Vegemite in a dessert. These Vegemite caramel pots with dark chocolate ganache are are nose-bleedingly amazing because Vegemite isn’t one of my favourite things (I don’t mind it scraped over water crackers, but that’s about it) yet I have made a dessert that, to be frank, impressed me.

It impressed me because the flavour works amazingly well (Vegemite and caramel – the new flavour pairing that will take the world by storm, just you wait and see) but also… it may be the world’s richest dessert. It’s so rich it could probably buy several hotels in Dubai. The Vegemite jars I served the stuff in that you can see in the photos – that much of this stuff would feed about 4 people. I ate about three tablespoons before I started to feel like my stomach was going to start convulsing in protest. Which means: my work here is done.

Read on for the recipe for Vegemite caramel pots with dark chocolate ganache.

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18 Comments by on November 12, 2010
filed in Baking, Not baking, Science, Sweet
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Things to consider before becoming a full-time professional dairy product reviewer


Go get a nice little spoonful of the bitter compound 6-n-propylthiouracil. Taste it. Can’t taste it? Ok, listen to me — never become a writer. Nip that in the bud right now.

Or at least never write about dairy products. Just… do us all a favour and… don’t. The world doesn’t need your rigid, prosaic descriptions of dairy products.

Maybe you’re one of those rare people who doesn’t have 6-n-propylthiouracil in their household or workplace chemical cupboard. If so, go to the fridge. Get out the cream cheese. (Don’t you dare tell me you don’t have 6-n-propylthiouracil or cream cheese. That is unfathomable and disturbing.) Eat a little piece of it and think carefully. Now, write a description of it. What’s important to you about it? What does it look like? What tastes and flavours can you pick up? What’s the texture like? Write it down on a piece of paper, hand it to me, and I’ll read it and shake my head disapprovingly if you’ve said anything as naff as “sweet”, “sour” or “milky”. Such an unimaginative and uninspired attempt at imagery… it could only have been done by a person whose pretty poor at tasting 6-n-propylthiouracil. Shame on you.

As I mentioned in the previous post, the different levels of sensitivity people have to bitter tastes can be associated with different behaviours. People who have greater sensitivity to bitter chemicals such as phenylthiocarbamine and 6-n-propylthiouracil (PROP) may perceive food differently, perhaps finding bitter foods less palatable (depending on the bitter compounds in the food, the intensity of the bitterness, and so on), which is a bit of a worry if the bitter foods are also healthy ones. However, it looks like the gene variant combination that bitter tasters have compared to non-tasters might also be associated with other differences in food perception. Fat content seems to be one of those, with research finding that people who are good at tasting bitterness also seem to be pretty good at discerning fat content and creaminess in foods. And they’re better at describing these things too. (And our fingers continue to hover over the button to purchase bitter taste phenotype kits so we can finally figure out how all of this stuff applies to us…)

Participants in a study by Kirkmeyer and Tepper evaluated various dairy products (such as cream cheese, condensed milk, sour cream, milk, ice-cream and yoghurt) and described each of the products in terms of appearance, taste/flavour and texture. A rather interesting pattern became evident once the participants were sorted according to their gene variant combination (genotype) for tasting the bitterness of PROP.

Non-tasters used very simple terms and a limited vocabulary — products were described in terms of being sour or sweet or milky; all the more basic and obvious descriptors for something like a dairy product. PROP tasters, however, used a much more varied lexicon, favouring descriptors such as “rich, buttery, creamy, light, grainy, gritty and sandy” in their evaluations. When comparing the descriptors in terms of whether they describe the sweet-sour dimension of the products taste or its flavour-texture dimension, it became apparent that tasters tended to place more emphasis on the flavour-texture dimension rather than the sweet-sour dimension, whereas non-tasters gave flavour-texture and sweet-sour equal importance.

This tells us that maybe bitter tasters judge creaminess and fat content using different cues to non-tasters, more related to the texture and the sensation of the food in the mouth. A few studies have found that tasters (or at least supertasters) are better at judging the fat content or creaminess of a liquid dairy product than non-tasters, so if they are using different cues, then they’re possibly the more accurate ones to use. But why are people who are good at tasting a particular bitter chemical better at judging texture?

Maybe the papillae, the tiny little lumpy structures on the tongue, some of which harbour taste-buds. PROP supertasters tend to have a greater density of tongue papillae, allowing perhaps for a more sensitive and nuanced perception of whatever’s on the tongue. So somehow, maybe the PROP gene is associated with the gene/s for papillae formation and expression.

The upshot of all of this is that it could be interpreted from a health perspective. Some research results suggest that not only are PROP tasters better at judging the fat content and creaminess of food, but that they also have a preference for the higher-fat, creamier food because, well, they can tell the difference. Give them low-fat ice-cream and they can tell it’s not as enjoyable to their energy-craving brain as full-fat ice-cream, but give the low-fat ice-cream to non-tasters and maybe they don’t care so much. Is this genuinely the case? And if so, does it affect long-term food intake and healthiness? Unfortunately, not much research has looked at whether these potential health concerns are, well, actual health concerns that we should be concerned about. All in good time, though.

In the meantime, PROP non-tasters: not the best dairy product reviewers.

In the mood for dairy, then? There’s plenty of cream on these chinotto black forest cupcakes. Yep, chinotto. This is, like, the flavour combination of the year for me. I don’t even like chinotto that much by itself, but paired with chocolate, it could not be more flawless. A cursory Google search reveals no other mentions of the chinotto-chocolate — CHINOCOLATE, if you will — combination, but maybe I can start a trend. You will try it, yes?

And you don’t have to go with my elaborate Russian Constructivism-inspired cake decoration if you really don’t want to. I don’t have the time to hunt you down if you don’t do it.

Read on for the recipe for chinotto black forest cupcakes with whipped cream and chocolate cherry truffles.

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11 Comments by on November 4, 2010
filed in Baking, Science, Sweet
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The bitter truth – now in genotype form!


Isn’t this a fantastic scenario: you’re sitting at your desk and a mysterious white powder floats through the air and lands on your face. Some of it lands on your lips and, being the risk-taking individual that you are who is apparently not averse to putting unidentified powders in your mouth, you taste it and immediately complain to your colleagues about how disgustingly bitter it is. The powder has landed on their faces too and they taste it too and… no, it doesn’t taste of anything, actually. It’s not bitter in the least, they say to you with suspicious eyes and 50% of their eyebrows raised. Well then, aren’t you quite the weirdo? Please take your imaginary bitter taste and go sit in the corner.

This is how they discovered that people can experience tastes quite differently from each other. It was only 1930 when A.L. Fox accidentally released some phenylthiocarbamide into the air in his lab while trying to create an artificial sweetener and it landed on the faces of his colleagues (good work!), and while some of them complained of its bitterness (you’d think that would be the least of their problems if they’re working in a lab where chemicals routinely drift onto their faces and into their lungs), Fox himself couldn’t taste the bitterness. It turned out that about 30% of people find phenylthiocarbamide tasteless, whereas the rest find it moderately to intensely bitter.

It’s not exactly uncommon knowledge now that the ability to taste bitterness varies from person to person and that this is down to genetics. A whole heap of studies over the years have looked at how genetic variants within the TAS2R family of genes mean that some people taste bitterness of particular substances more easily than others. For TAS2R38, the gene that codes for the protein that allows phenylthiocarbamide to be tasted, you can have one of three possible combinations of variants, allowing you to be either a non-taster, a medium taster, or… a supertaster, in which case you can taste that phenylthiocarbamide better than about 75% of the population! Well done, you.

So, like I was saying, we know bitterness perception varies from person to person due to genetics, but it’s kind of boring if you just look at that within the scope of “Oh, Person X can taste this very specific chemical really easily whereas Person Y can’t taste it at all”. Pretty limited relevance. The interesting part is how it affects behaviour — how well you can taste bitterness can affect how much you like particular foods, and that can have a reasonably big impact on eating behaviours.

Studies have been a bit inconclusive when it comes to bitterness gene variants and liking for somewhat bitter vegetables (such as broccoli, spinach, Brussels sprouts, kale and cucumber), with high-tasters of bitterness sometimes liking these vegetables more than low-tasters, and sometimes less. However, sensitivity to bitterness changes with age, so maybe you need to look at these things in particular age groups to get a clearer picture. Certainly, some studies have found that in children, non-tasters who aren’t so sensitive to bitterness find these vegetables more pleasant to eat than the tasters who are sensitive to bitterness, and non-tasters generally eat more vegetables than tasters. Some studies have found the same in adults.

Consumption of bitter fruits can also be affected by genes, with female adult supertasters finding a drink containing naringin (a compound from grapefruit peel) less pleasant, and the same went for just plain grapefruit juice. It looks like the intensity of the bitterness matters too, since taster children were no different from non-taster children when drinking a mixture of 25% grapefruit juice and 75% orange juice, but then the tasters disliked a more bitter mixture of 50% grapefruit juice and 50% orange juice compared to non-tasters.

So it all sort of makes sense — people who are more sensitive to bitterness kind of dislike things that are a bit bitter. However, the intrigue continues with research that has found that genetic variants for bitterness are also associated with different perception of sweetness and saltiness and sourness, the detection of the pungency or flavour of food, and also the ability to discriminate fat content in food and drinks.

But I will go into detail for those in future posts, and for now, you can make some Pimm’s Cup cupcakes. Complete with whipped lemonade and simulated cucumber! It’s a bitter orange and cucumber gel, cut into sticks, to which I attached real cucumber skin. Don’t you want to do something so convoluted and arduous too?

Read on for the recipe for Pimm’s Cup cupcakes.

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16 Comments by on October 31, 2010
filed in Baking, Not baking, Science, Sweet
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