Here is my Step-by-Step Guide (with photos) of how I make Tomato Passata, or Tomato Pasta Sauce. It can be a variable process, and I am sure many of you do it a different way to me! For those who know very little about it, I hope this helps you to go forth and find what works for you, keeping food safety in mind. What does passata mean, I hear you ask? It comes from the Italian passata di pomodoro, which means it has been 'passed' through a sieve to remove seeds and lumps... passata is just tomato puree, but sounds better! You can use this straight away, but I make it in bigger batches for preserving in my Fowlers Vacola Preserving Unit. I love using homegrown, organic tomatoes, and homegrown herbs and garlic too, if I have them. The taste of homemade pasta sauce is great, you know what went into it, and you can preserve it to use all year long in non-BPA jars (if using Fowlers Vacola jars/ lids). It also feels satisfying to know that it is a skill I have, and one that I can pass on to my children. Not to mention the feeling I get when I see pantry shelves full of jars of homegrown, homemade pasta sauce!
Please read my posts Preserving in a Fowlers Vacola Unit - Equipment, Resources, FAQ & Tips, and Step-by-Step Guide to Preserving in a Fowlers Vacola Simple Natural Preserving Unit.
Start with fresh, ripe tomatoes... organic and homegrown if you can. In my garden, the tomatoes don't always make it to that deep red 'ripe' stage before I pick them, because if I leave them til then, I often find them ruined by bugs! Of course, tomatoes don't ripen on the vines at the same time either, so I pick those that are red and almost ripe, and sit them on the kitchen benchtop until I can pick another batch in a couple of days time. That way, once I have a decent amount, ie. several kilos (4 to 5kg), I can do a big batch of pasta sauce, which is more efficient. If you are a purist and only want to use perfectly ripe, deep red, lush tomatoes in your sauce, good for you!
If I have the oven on (for other things), I roast the tomatoes. I find this heightens the flavours. I do not add oil when I am roasting tomatoes. I don't mind using a mix of fresh and roasted tomatoes in my sauce, depending on what I have ready when I notice I have a large amount of tomatoes building up! Putting the oven on in Summer means a hot house, and I prefer not to turn it on just for one thing anyways. (I have used my Solar Cooker for 'roasting tomatoes' too, but that 'stews' them, more than giving the caramelised flavours of roasting). I find with the roasted tomatoes, I can keep those in the fridge for a couple of days (or even freeze them) until I have another batch of ripe tomatoes ready. This makes it more efficient, as I can do less washing up, less time of having the slow cooker plugged in, and maximise the use of my Fowlers Vacola preserving unit!
How to seperate the tomato pulp you want, from the seeds and skin you don't. I have a Squeezo, which I did buy in from overseas. It is mostly all metal (just a rubber gasket & plastic on handle). You don't need to chop or peel the produce, which appealed to me. I find the Squeezo is easy to put together, easy to use, and relatively easy to clean and store. You do need to oil the drive shaft part before storing. The mesh sieve roll, or 'screen', part can be tricky to get tomato skin out of too, when cleaning it. I am glad I have it. Others have Moulis, passata machine, food processors, or just a sieve, a spoon and some hard yakka! The first photo of this post, shows you how I set it up on my table (it clamps on, and my kitchen benchtop doesn't have enough area to clamp to) with bowls to catch the tomato puree, and another to catch the skin/ seeds. I also have a few well placed paper towels to catch any drips. Wear an apron when you are doing this, by the way!
You add the tomatoes to the Squeezo hopper and start winding the handle, to make the drive shaft (ooh, 'Lost' flashback!) turn the scroll and push the tomato pulp out through the screen. As you keep 'squeezing', the skin and seeds continue along the scroll (not through the screen, or sieve part), and come out the other end into a bowl. I find it useful to scrape down the 'screen', usually using a spoon, but I had the back of my knife on hand when taking this photo! Just scrape it into the drain tray, and it slides down into the bowl below.
I use the wooden plunger to help press the tomatoes through the hopper and into the scroll/ screen.
I cut my tomatoes into halves or quarters to check for grubs or bad parts. I find it easier to chop them all and put them into a bowl, before I start the process of 'squeezing' in the Squeezo. You could put tomatoes in whole, of course, if you prefer. I find the little tomatoes, like cherry or red fig, are very resistant to grubs and disease, so they sometimes get thrown in whole.
Wa-la! The tomato pulp or puree slides down the drain tray into a bowl I place there. As the bowl fills, I take it and add the tomato puree to the slow cooker, then quickly replace the bowl under the Squeezos drain tray, before the next lot comes out of the Squeezo. A seperate bowl catches the seeds and skin, which can go into the compost (or bin, if you don't want your compost to make a wild tomato jungle of your backyard next Spring). Once all the tomato puree is in the slow cooker, it can be reduced/ cooked.
From pureed tomato to thick, rich tomato passata. I use my slow cooker, rather than in a pot on the stove-top, as I find it hard to get it to simmer on my stovetop, even with gas at the lowest settting. I also find I am not there to stir it enough and it can burn. To my 6 litre slow cooker full of tomato puree, I add several cloves of fresh, crushed garlic, a few basil leaves, and a tablespoon full of thyme. You can add salt to taste (I add about a tablespoon). I put the Slow Cooker on Low, and let it reduce for several hours, usually all day (8 to 12 hours) until it is thicker and rich in flavour. Once it is reduced, you can eat it straight away, or bottle & preserve it. (I also reduce it more to make 'pizza sauce'). Whatever doesn't fit into a bottle, I put that into the fridge, or I freeze it. As I am bottling the sauce, I add citric acid to each bottle (see below). You must boiling-water bathe jars of tomato passata before storing them. More about preserving in a Fowlers Vacola unit coming soon.
Tomatoes are considered a high acidic food in preserving terms, which means they are safe to process in a 'boiling water bath' (as opposed to having to 'pressure can' them, which is what low acid foods need to be preserved safely. Some more information about the two methods). However, tomatoes are borderline (being on the lower end of the 'high acid' foods, and some breeds not being as acidic as other) so, recommendations are to add lemon juice or citric acid to the jars of sauce before processing. This increases their acidity and therefore, the safety of the product being preserving. This is especially apt for a passata with some herbs and garlic added. The Fowlers Vacola 'Secrets of Preserving' guide book lists their recommendations as:
- No. 20 sized jars (600mls) - add 2 teaspoons of lemon juice or 1/4 tsp of citric acid
- No. 27 (900mls) or 31 (1000mls) sized jars - add 2 teaspoons of lemon juice or 1/2 tsp of citric acid
- No. 36 (1250mls) sized jars - add 2 tbsp lemon juice or 1 tsp citric acid
Please read more about food safety when preserving, here:
- CSIRO - Small-scale commercial preservation of acid foods
- USDA - Selecting, Preparing and Canning Tomatoes and Tomato Products