# Why does my cookbook want me to drain my tomatoes for a pasta sauce?

I have an excellent recipe for pasta sauce, but I'm having trouble convincing people to try it because it contains a counter-intuitive and potentially wasteful instruction.

The gist of it is this:

1. Take a tin of plum tomatoes
2. Pour the tomatoes into a seive and smush up the tomatoes themselves, draining away the tomato juice
3. Heat with a teaspoon of sugar and a generous pinch of sea salt

The resulting sauce is extremely addictive, but why do I have to drain the tomatoes? Tins of plum tomatoes aren't hugely expensive, but neither are they cheap, and I don't know why we'd want to waste tomato juice. Is it for the sake of taste (perhaps the juice is bitter?), or for texture instead?

• Convincing people to try eating it, or cooking it? – GdD Jun 16 '13 at 19:54
• You're not wasting anything with most canned tomatoes as all you are losing is water added in the canning process. If it was expensive, high quality tomatoes I'd think twice but for most tomatoes it makes perfect sense. – GdD Jun 16 '13 at 19:55
• @GdD - cooking it, but I think if I get them to try it, that problem might resolve itself! – Jimmy Breck-McKye Jun 17 '13 at 19:34

The main purpose is to allow you to get a thick, hearty sauce more quickly. By pre-draining the liquid, you lose a a very small amount of flavor, but save time and energy in reducing the sauce. Otherwise, you would simply have to boil away the excess liquid to get the desired consistency.

Draining some of the juice allows you to get to a thick sauce quickly. It may also reduce some of the acidity which may be why you prefer this recipe.

The thickness of the pasta sauce goes hand-in-hand with the shape of the pasta you're making.

Different pasta shapes can hold different amount of water (say fusilli vs spaghetti) and traditionally you boil down the sauce to make it thicker so the pasta can hold it. However, this can have other effects including change of colour.

You can save the tomato juice and make a mean bloody-mary/ceasar with it. Throw in some worcestershire sauce, tabasco, a stick of celery and optionally a stick of dried meat (e.g. beef jerky) and it's a meal onto its own.

Tomato juice is also a great hangover cure. so either way, you can save the stuff and not waste it.

• While there is certainly traditional variation in pasta shapes across Italy, is there any evidence that they actually hold significantly different amounts of water? That sounds like an old nona's tale, much like "you must have a large volume of water to boil pasta." – SAJ14SAJ Jun 17 '13 at 14:49
• physics, says if water sticks you and you have more surface area, you hold more water. e.g. Regular Penne with ribbs holds more water trapped in the ribs than Penne Lisce. – MandoMando Jun 17 '13 at 15:00
• significant mando, significant. There are lots of true but non significant facts. For example, adding salt to the water raises its boiling temperature, except at culinary concentrations the effect is so small is to be completely negligible. – SAJ14SAJ Jun 17 '13 at 15:02
• To the Italians that bother making traditional variations it is significant. I certainly notice it, and it is enough to save guests from seeing their pasta resting in a puddle of soup. You can run your own experiments if you so desire, though. – MandoMando Jun 17 '13 at 15:15
• @SAJ14SAJ I'll be the first to say that sometimes tradition is based on bad assumptions, but in this case, the facts are both true and significant. This isn't a .01% boiling point elevation difference; for example, capellini has about twice the surface area per volume of spaghetti. – Cascabel Jun 17 '13 at 17:25

It can make your sauce watery and almost impossible to reduce in time for dinner. What I tend to do is drain them off and reduce the remaining liquid in another saucepan while the main pasta sauce is cooking and then add in the end when it's the desired consistency. I suppose it depends on the brand but one must assume that the juice contains a significant amount of water soluble vitamins and taste - my pasta sauce always has an intense rich tomato flavour.