Archive for August 21st, 2008

On the solidification of ice-cream

August 21, 2008

A nice piece by Maria Brumm at Green Gabbro (with wonderful micrographs too — to go with it):

Much like igneous rocks, the same liquid mix can turn out very differently depending on what happens while it is freezing. The goal of most ice cream and sorbet is to have a smooth and creamy texture, which would be ruined by the presence of large ice crystals. To achieve this, you want to cool your ice cream so quickly that the crystals don’t have time to grow, and keep the mixture stirred up while it freezes. There’s a lot of energy involved in the transition from liquid to solid water, and a home ice cream maker can’t do the heat transfer quickly enough to keep the ice crystals small, so you have to sit there and turn the crank until your arm is sore while the mixture slowly freezes (or invest in a fancier machine that will do the stirring for you).

Or, you could acquire some liquid nitrogen – by pouring a -321º liquid (that’s a mere 77 Earth units above absolute zero) into your ice cream mix will freeze it so quickly that stirring is neither difficult, nor tremendously important. The crystals will be tiny no matter what. This method has the added advantage of being able to freeze mixtures whose melting point is below what you can get with home freezers and rock salt, enabling such monstrosities as a silky-smooth 80 proof rum raisin.

The difference between ice cream and sorbet is that ice cream contains cream and sometimes eggs or other emulsifying agents, while sorbet is just fruit, water, and sugar. The presence of fat and emulsifiers in ice cream provides another way to control the crystal structure (and another way to ruin the texture, if you let the fat globules get too big) but there’s no direct analog for this in igneous petrology.

Occasionally, you do want a dessert with a sharper texture to it, or maybe you’re just too lazy to stir very often. That’s how you make a granita: Leave the sugar slurry in the freezer, so that the crystals have time to grow, but interrupt the process every half-hour or so, so that they don’t get too big. You end up with a slushie or crystal mush.

Link via B-squared. The latest post of Brumm also talks about a book called The science of ice cream — which sounds like an interesting read; the blog looks like a good read too. Take a look!

Chabon’s writing– not legitimate?

August 21, 2008

Vivian Gornick, in this interview, claims that it is:

Roth and Bellow are titanic figures, they’re beyond criticism. But really, what I am saying in this piece is that Jewish writing is over. That is the point of contention.

Jewish-Americans did something in American literature that no other culture has done— they created world-class literature out of the immigrant experience. And that’s the only thing that mattered in Jewish-American writing. Had Roth and Bellow not been major talents, you wouldn’t have Jewish-American writing. It wouldn’t mean anything. It would just be parochial, local.

But we cannot have major talent writing this stuff anymore because there’s nothing to write about. What made them major was their gripe, the chip on their shoulders. The rage that they felt at the world for keeping them out. That experience became a great metaphor. There is no hyphenated Jewish experience anymore. I have two nieces who are both Ivy League babies and they’re in the ruling class. There’s nothing they can’t do. Nothing.

So there’s nothing to talk about. There’s really nothing to write about. Yet you have young people who keep on doing it. All I’m saying is, it doesn’t count. Take Michael Chabon, or Jonathan Safran Foer. They’re cashing in on a world that’s long gone and they’re writing with open nostalgia. They’re making things out of it that belong to their grandfathers. It’s a habit to go on assuming that this is legitimate writing. But I truly feel it is not.

Link via Amitava Kumar.

Key to creating world class universities

August 21, 2008

T T Ram Mohan at The Big Picture addresses the question (while commenting on a recent piece by Dinesh Mohan in Business Standard):

Forget the notion, currently popular, that in order to create world-class universities, we need government to get out of education. Forget also the notion that private institutions, motivated by profit and charging appropriate (that is, sky-high) fees will do the trick. Think again about the notion that you need fabulous pay packages in universities in order to attract talent- no, the types who are attracted look for job security, decent pay and a supportive environment.

We need to strengthen the IIT-IIM model and give it wider application. At least where the IITs are concerned, fees remain reasonably low and affordable and they must remain so. Improved governance at generously funded state institutions and inclusive, affordable education are the key to creating world class universities. In short, the drift towards privatisation, higher fee and higher pay packets for faculty as the answer must be checked before it is too late.

Take a look!