Ask HN: How big are your tablespoons?

32 points by Tomte ↗ HN
This is kind of random, but I was watching a cooking video where the presenter said things like "we add two tablespoons of olive oil", and it looks like they pour much more than that.

And that has been my feeling all along. "Sprinkle a tablespoon of kosher salt on a chicken"? That seems very little.

Then I googled "1 tablespoon to ml" and found that about 15ml is the definition of tablespoon.

I just measured mine. They hold 10ml, and I consider them regular size.

Are American tablespoons larger? Or is the measure "tablespoon" independent from actual utensils, and whenever you read "two tablespoons" in a recipe, you know to pour three actual tablespoons?

98 comments

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The last. The measure "tablespoon" is indeed independent from actual utensils, and is measured with a set of tools for that purpose, as you would with ml.
Thanks! I knew about the possibility, but was clinging to my German ways (we do use tea and table spoons when the recipe tells us to).
I use wolframalpha and convert everything to millilitres and grams as appropriate. Most times you don't even need to distinguish between volume and weight because wolframalpha also does that conversion for you.
To not have to go to DDG or WA manually, I wrote a script to convert stupid measurements on a page, but I can't say it turned out very well.

In case someone wants to try it out or improve it, open a recipe website and run the code. Or uncomment the console.log() line at the bottom, comment out the document.x line, and run it from the command line (`js code.js`).

    // todo:
    //    - °F matches hex codes ("abcd64fabcd")
    //    - fluid ounce?
    //    - "([0-9]{2,5}) degrees" especially when N > 300
    
    var test = 'Take 1/4-1/2 cup of water, 3 1/2 c. marinara sauce, two ounces of potatoes and three to five tbsp gold.\nOr perhaps 1/8 oz. of gold.\nBake at 350F or with degrees symbol 350°F!';
    test = 'one 29 oz can black beans, rinsed and drained\none 6 oz can tomato paste\n32 oz vegetable stock\n1 onion, chopped\n5 cloves garlic, minced\n1 tablespoon chili powder\n1 tablespoon cumin\n1 teaspoon oregano\n1 tablespoon olive oil\n1 sweet potato, peeled and cut into bite sized chunks\n1 cup dry quinoa\nsalt and pepper to taste\navocado, cilantro for garnish  (optional)\n\nHeat the oil in a large heavy soup pot over medium low heat. Add onions, and cook until soft and they start to turn brown (about 10 minutes). Add the garlic, and cook for about 2 minutes.\nAdd the tomato paste, chili powder, cumin, and oregano and cook for about 2 minutes, stirring constantly.\nAdd the beans, stock, and potatoes, and season with salt and pepper.\nCook for about 5 minutes, then add the quinoa. Continue cooking for about 15 minutes – 30 minutes, stirring frequently, until quinoa and potatoes are cooked and the chili has thickened.\nAdd a bit of water if the chili becomes too thick for your liking. Top with avocado and chopped cilantro. Scrumptious!';
    test = 'Chocolate is very sensitive to high temperatures and different chocolates require different maximum temperatures. Dark chocolate should never be heated above 120 F, while milk and white chocolates should never be heated to above 110 F. It is quite easy to exceed these temperatures if using a double boiler with boiling water, or if microwaving on full power'
    test = 'one 29 oz can black beans, rinsed and drained\none 6 oz can tomato paste\n32 oz vegetable stock\n1 onion, chopped\n5 cloves garlic, minced\n1 tablespoon chili powder\n1 tablespoon cumin\n1 teaspoon oregano\n1 tablespoon olive oil\n1 sweet potato, peeled and cut into bite sized chunks\n1 cup dry quinoa\nsalt and pepper to taste\navocado, cilantro for garnish  (optional)'
    
    function fixSizes(str, debug) {
     var SIprefix = function(amount) {
      if (amount > 1000) {
       return (Math.round(amount / 1000 * 10) / 10).toString() + 'k';
      }
      if (amount < 1) {
       return (Math.round(amount * 1000 * 10) / 10).toString() + 'm';
      }
      return amount.toString();
     };
    
     var volume = function(amount, ratio) {
      return SIprefix(amount * ratio) + 'l';
     };
     var weight = function(amount, ratio) {
      return SIprefix(amount * ratio) + 'g';
     };
     var fahrenheit = function(amount) {
      return (Math.round((amount - 32) * (5 / 9) * 10) / 10).toString() + '°C';
     };
    
     // units = [ [from, type, rate], ... ]
     // from = list of names, e.g. ['ounce','oz.']. The 's' suffix is automatically checked for, so you don't need to specify 'ounces'.
     // type is one of weight, volume, fahrenheit.
     // rate is: if weight, the ratio of $from to grams; if volume, the ratio of $from to litres; if fahrenheit, omitted.
     var units = [
      [['°F', 'F'], fahrenheit],
      [['cup', 'c.'], volume, 0.25],
      //[['tsp.', 'teaspoon'], volume, 0.0049],
      //[['tbs...
Don't know if it's the same in the US, but in the UK there's also the desert spoon, that you'd eat rice-pudding with; a tablespoon is only for serving or measuring, you couldn't fit one in your mouth (unless you have a really big mouth). Could this be the issue?
An american tablespoon is as UK desert spoon. The UK tablespoon is much bigger than the american one.
Do an image search for "measuring tablespoon". It's a dedicated piece of silverware, distinct from a regular tablespoon.
Alternatively you can just eyeball everything.
One eyeball holds about 24mm, way too much to approximate a tablespoon
This. Plus you can usually just taste it as you go and adjust.
It takes about 10 minutes and a box of salt to master how to use your cupped palm to measure teaspoons and tablespoons. I’d recommend anyone that cooks take the time to do it and you won’t ever need measuring spoons again.
It would be interesting to take all the measures that refer to real objects (tablespoons, feet, stones, etc...) and to compare them to whatever "average" of actual objects we can devise.
"Stone" is a particularly fun one. It's akin to measuring length in "pieces of string".
"Chains" is currently used measurement for length.
I own a book with that exact topic. Unfortunately it's only available in German probably because it's a very niche interest. It's called "Das Maß im Kochen", roughly translated as "The measure in cooking" or "Measurement in cooking" by Renate Breuss.

For instance it contains a chapter about time durations that have historically been measured or compared to the time you needed walking a known length. Presumably in a time where not everyone owned a watch.

Americans often have set of measuring spoons (https://www.amazon.com/s?k=measuring+spoons) that have 1 Tablespoon, 1 Teaspoon, 1/2 teaspoon, 1/4 teaspoon (some have 1/8 teaspoon too). As you found, a Tablespoon is an "exact" measurement and most don't use their actual eating utensils for cooking - though I'm sure at one point they were used.

Often I've found with watching cooking shows (and some of my own experience) when hosts say something like "add a ___ of blah" and then proceed to just pour it out of the container without exact measurement the reason they are giving a measurement is to give a rough approximate of how much but the exact amount doesn't really matter, though it never hurts to go towards the smaller for things like seasoning.

In terms of baking recipes (bread, cakes, cookies, etc) the exact amount matters more (chemistry or live things) but you can still be off by a bit and things will still work.

As a Brit, I found it useful to source a set of US measuring spoons in order to deal with US recipes without conversion.
Worth noting that the teaspoon to tablespoon ratio is 3:1. Measures that are evenly divided into three are common in the English system. So common that despite having eight ounces in a measuring cup, the one third cup is part of a standard set of measuring cups.
I juggle this kind of stuff in my head, teaspoons, tablespoons, cups, ounces, pints, quarts, gallons; 1/4 inch, 5/16 inch, 7/32nds, foot, yard, mile and...

I can see why some people like the metric system.

One of the first things Thomas Keller says in his Masterclass course is to drop these, get a good quality measuring scale and use grams.

I suppose that as someone with two three-star restaurants, consistency matters.

Try mechanical/civil engineering in Canada.

Most projects are metric, or at least, I prefer working in metric when I can. However, things like raw materials (ie sheet steel and similar) are only sold in us customary units, or worse, gauge measurements. Cutting tools for machine tools (drills, mills, lathe inserts, etc) are also much more common in US units than metric

I'vr pretty memorized the millimeter equivalent of most fractional inches, up to sixteenths, by now. I've also worn the silkscreen off the 2, 5 and 4 buttons and finally broken the 5 switch on my previous calculator, bfrom the sheer number of multiplications and divisions by 25.4 I've done.

Also, in terms of chemistry, measuring the volume of components (e.g. of powdery substances like flour) rather than their mass is really not a good way to determine the exact amount.
I wish it was common practice to do everything by weight! Measuring by volume tends to have a lot of more error due to manufacturing of the measurement device, packing of the material, and density fluctuations
I can't say I'm sure how I would measure an ounce of sugar...
A kitchen scale? You don’t weigh the amount, you add until the scale with your bowl on it registers an increment of that amount.
A tablespoon of sugar--a common amount in a recipe--is 12.5 grams. As the other guy said, a kitchen scale can easily do this: throw your bowl on there, hit the "tare" button to zero the scale, and then any sugar you add will be the reading on the scale. No spoons or cups needed; it's simpler! Tare again and add the next ingredient.
Whoa, okay, you've convinced me! I'm on board with this!
This would drive me crazy. Unless you're baking why do you need such specific amounts of things like sugar? Just taste the dish and add more sugar if you need it.
Using measuring spoons instead of a scale drives me crazy. Even basic recipes benefit from mise en place and wiping/cleaning measuring spoons to do that is maddening. When using a scale the task becomes a simple matter of counting in just the same way as using measuring spoons. Using grams is the real win. Having everything in a base 10 system means less math in your head while managing the rest of the kitchen.
Well, unless you need to divide a recipe down. Base 10 isn't optimal for everything.
If I'm baking bread or a cake or something that really needs exact amounts yes. Strict mise en place and measuring things by the gram for basic recipes seems like major overkill to me, I'd eyeball everything and avoid dirtying the measuring spoons at all. Maybe I'm lazy.
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How do you taste an uncooked cookie dough?
That falls under baking IMO.
I have a simple kitchen scale, it has become indispensable.

I measure everything: 100g of pasta if I'm not too hungry, 22g of coffee beans for 300g of water etc

And don't think I'm particularly OCD, it's just so much more convenient to have repeatable results.

100% this. I initially bought the scale so that I could have a scientific and repeatable process for making coffee, but now I use it for everything I eat and make. It's become second nature now.
As a European that's like hearing someone say they have no idea how to measure the width of a box (measuring tape or ruler), an amount of water (measuring cup), or an amount of a solid that won't nicely fit into cups or spoons (e.g. apple). You never came across a recipe that called for 200g sugar and 400g flower, for example?

From someone who watches american vlogs I heard that everything in the USA is cups and spoons. It makes me wonder: doesn't it get old to have to clean the cup and a set of spoons after every use? Why not pour directly into the mixing bowl that you put on a scale?

> doesn't it get old to have to clean the cup and a set of spoons after every use

sort of, but I just measure all the dry ingredients first, then the wet ingredients, and then put the cups/spoons in the dishwasher

> Why not pour directly into the mixing bowl that you put on a scale?

Recipes here very rarely give weights.

> You never came across a recipe that called for 200g sugar and 400g flower, for example?

Not in any American recipe book or web site. It's always by volume. This makes baking extra difficult.

It’s a joke. An ounce is both a unit of volume and weight...or rather two units of weight. The two units of weight are less of an issue when cooking because gold is rarely eaten at all and certainly not in troy ounce quantities.

Sugar is sold by weight but measured by volume when cooking...and not in volumetric ounces but using cups and fractional cups...a cup being eight volumetric ounces.

The nexus between volumetric ounces and avoirdupois ounces is a pint of water is sixteen volumetric ounces and weighs about one avoirdupois pound and an avoirdupois pound weighs sixteen avoirdupois ounces. A roundabout way of sayin “a pint’s a pound the world around.” Obviously empire induces certain conceits.

An advantage of volumetric measuring is using utensils rather than mechanisms. A measuring cup can hold a cracked egg and a scale can’t...which also points out that the variability of eggs and walnuts suggests that gram accuracy is not warranted for ordinary cooking...you probably don’t adjust the weight of flour based on its moisture content.

Even better, they're using mass which will allow the same recipes to work on Mars.

/s

You assume that chemistry works the same in different gravitational fields of different strengths!! How plebian!

Also: /S ;)

The increased accuracy often doesn't really translate to a better result though. And many people will taste test while cooking so that mistakes can be fixed.
Exactly! It doesn’t really make sense to make recipes overly precise. It also depends on the tools available, the brand of oil, etc etc. Too many fluctuating variables.
I grew up in a region where everything in recipes is given by weight and learned to cook this way.

Nonetheless, although initially super annoyed, I have grown some fondness of using cups as measurement. For day to day cooking, I can’t be bothered to do things precisely and I’m more interested in rough ratios. Usually I don’t use any measurement device at all.

Also, no matter which way, often you can not rely on measurements because of how widely the products differ. For example paprika powder. The exact same amount can go from not doing anything discernible for the dish to overpower it.

My favorite way of cooking is how it was done in a half day class I took in Singapore. There were some basic amounts given as a starting point, then all further instructions where: do this until it becomes that consistency or color, taste, if you want it spicier add some more of this, if you want it more sour add this, sweeten with that if you like, taste again, etc.

Exact measurement I think is great for certain dishes where it really matters and for professional places to make it reproducible and scalable, but at home, for me it takes like half the fun out of it and I reckon more people would enjoy cooking if recipes where generally conceived, less as instruction manuals and more as seed for an idea for experimentation.

For main ingredients, sure: when baking bread, I measure flour and water into a bowl sitting on a kitchen scale, and it's great.

But there's no way that I could measure the yeast with my kitchen scale! When a (US) recipe calls for "1/4 tsp yeast", I'd be lucky if that were even one gram, and that's my scale's resolution. Same for salt, and for lots of other seasonings. (I suppose I could get a high-precision lab-grade balance for that sort of thing? Seems a bit more complicated than just using a few measuring spoons.)

That said, I completely agree about the ambiguities involved. If anyone out there happens to know what the heck "1/4 tsp of saffron threads" is supposed to mean, I'm all ears. (Thoroughly crumbled, I'll bet I could fit $20 of saffron into 1/4 tsp. Not crumbled at all, even half a dozen threads arch up above the spoon like some sort of abstract wireframe sculpture.)

I have two scales for cooking, one of them a "drug scale"* with hundredth gram resolution. It was as cheap as my kitchen scale. Still, I only use it for modernist ingredients like emulsifiers, where small variations can cause big outcome changes. For a quarter teaspoon yeast, yeah just use the quarter teaspoon.

Measuring by mass has a lot to recommend it, but converting a volumetric recipe to mass is not worth it. It's not as precise a process as you'd like and will still need ad hoc adjustments.

* All scales are drug scales, if you're bold enough

In Europe, it is common to use alternative measurements, for amounts where you’d need a lab grade or drug dealers scale. A tablespoon, a knife tip, half a sachet, etc.

At the same time it also used to implicitly indicate that how much you use exactly doesn’t really matter as long as it is in the ballpark.

I was actually offered a cook book where every measurement is in grams, including oil or spices (so yes, measurements like 0.5g are common in there). It's also typeset in LaTeX.

(Although tbf, I haven't ever actually use it except when looking up pancake batter recipe)

By weight alone probably wouldn't guarantee results. Consider, the same weight of dry firewood would still burn slower that that much paper/kindling.

One could argue those are different ingredients, and to an extent I can agree with that. However, the point is the same ingredient at a different density is practically a different ingredient. So the problem is some ingredients shift during rest into other ingredients.

Which, I don't think, is controversial. Whole milk and cream are obvious facets of this. And most different types of flour are visually indistinct. Then there is kosher salt versus table salt. Pretty sure those are not really substituted just by weight.

Besides the fact already mentioned that there's 2 completely different sizes of tablespoon, TV/internet chefs generally lie about the quantities and times of everything. How many times have you heard them say things like "cook the onions until they're dark brown - about 15 minutes", or "this step seals the juices inside the steak" or similar nonsense. I don't know why they do it, but they do.
The bigger treacheries in my book are the overly optimistic prep times, especially when it comes to chopping and dicing ingredients. Perhaps I’m just very slow, but it almost always takes me twice as long as listed on the recipe to prep ingredients.
Twice as long sounds about right. Optimistic even in some cases like when it calls for a sweet potato since that's irregularly shaped and needs to be pealed and chopped and is quite hard.

Maybe we need a "banana for scale" equivalent in cooking, where chopping time is defined as N times pealing a banana / chopping an onion. Or we just keep doubling the prep time of everything written in cook books, recipe websites, etc...

Your knives may be due for sharpening, and you might benefit from a different grip. Youtube is pretty good for knife skills.

Here's my favorite video on the internet: https://youtu.be/1y5h1pDHhzs

Heck, they don't even include the prep times in their estimates. "Dinner in 30 minutes!" ...assuming you already have all the veggies cleaned & chopped, and the oven pre-heated.
Prep time doesn't include chopping or measuring ingredients. You need to have the ingredients ready before the prep time starts. This is stupid, but people are used to it and like faster recipes so more and more of what should be prep gets hidden in the ingredient descriptions.

So if a recipe says "1/4tsp salt", the time to measure out that salt isn't part of the prep. If it says "10 carrots, peeled and diced", that's not part of the prep.

But if in its ingredients it says "10 carrots" and in the steps says "peel and dice the carrots" then that time is part of the prep.

while that is ridiculous, I suppose the differences in prep methods (hand chop vs. food processor) could lead to large variance in prep times, though anything is better than assuming no time for the preprocessing.
You can always buy a large bag of onions, watch some youtube videos, and spend the afternoon improving your knife skills.

I've learned to keep my mouth shut while watching others prep food. Compared to someone who has worked in a kitchen the average person is shockingly slow and inefficient. It's like when you watch someone using a computer that doesn't know about ctrl+c ctrl+v, or two finger types in https://www.google.com to start their search.

Here in the UK one of our TV chefs is Jamie Oliver.

He took a bit of a hit and ridicule in the papers when he brought out a TV/book series called '30 minute meals' and when people tried it most recipes took an hour.

It's because TV chefs don't measure anything, they go by experience and they usually get it right.

However they have to give you some measures because between what you think is a good amount of sugar and what he had in mind there might be a tremendous difference.

Don't get me started on their "pinch of salt" that is more salt than I use in a week of cooking.
You should use more salt. :)
Not according to my cardiologist :-/
:( I thought the modern take was that salt was over vilified. That said, I do not recommend ignoring a doctor. Best of luck keeping your health under control!
TY!

Salt for an average person most likely is over exaggerated. But once you already have hypertension, you need to watch it.

I'm not a cardiologist but I've read somewhere that when you have hypertension it usually isn't salt the problem but a lack of potassium (sodium and potassium have to be in balance in your body, can't remember the ratio).

The recommended thing was to eat a lot greens (particularly big salads) to have loads of potassium (not recommended in pills, might be dangerous).

YMMV, don't sue me etc ;)

And butter!

The average person would be appalled at the amount of butter and salt their favorite restaurant uses.

They always BS on the onion thing, especially for certain recipes, like a the bases for a lot of indian dishes they'll say 1 onion for 20 minutes when what you actually want is 3 onions for 40 minutes.
all my life... well, since chemistry class... I've wondered why recipes just aren't that precise.

My mom would smile and just handle it and I always wondered if it was a way to keep the menfolk out of the kitchen.

(I'm glad I can still buy pants by waist size and length)

Baking requires precision, regular cooking really doesn't. It's not an exact science, once you have some experience seasoning things you'll be able to eyeball the quantities as well.

Stuff like the grind size of your salt can affect how much you should use, so just volume or weight won't transfer between kitchens.

Also tasting and adjusting is always preferable to using pre-set amounts.

For cooking times: I notice that in winter stuff takes longer to cook/fry (if I have the window open). This is of course because it’s simply colder in the kitchen! So it is very hard to make recipes precise, as they depend on all the tools, And the humidity, temperature, etc of the kitchen.
Altitude really affects cooking too. I've lived at ~10k feet before and the cooking and baking times really are affected. For instance, water boiled at 88 C, not 100 C.
It really doesn't matter. Once you get experience cooking you can just improvise most things and know what flavors will work together in what amounts. As mentioned elsewhere baking is entirely different, though.
> "cook the onions until they're dark brown - about 15 minutes"

See also https://slate.com/human-interest/2012/05/how-to-cook-onions-...

Properly diced, and cooked in a heavy pan, you can brown onions in 15 minutes. Most people miss those two important steps though. And recipe authors mistakenly think the general population has the proper technique and equipment. Coarsely chopped onion in a dinky frying pan will take much longer.
The measure "tablespoon" is independent from actual utensils, as far as I can tell.

And who came up with the abreviations tbsp and tsp to mean different amounts?

Oh and 'cups', who came up with that?

Cups and spoons were popularized by American author Fannie Farmer. These measurements replaced earlier ones like a "handful of flour" or a"teacup full".
> Oh and 'cups', who came up with that?

A cup is 8 oz., unless you're measuring coffee, in which case it's 5 oz. instead. I forever got confused when buying coffee makers...

1 US cup is a little less than a quarter liter (actually 236.6 mls)

There are 16 tablespoons in a cup, which gives the ~15 mls you found.

Also note there are 3 teaspoons in a tablespoon.

In the USA, "tablespoon" is an official standard measurement of volume with a defined size. it doesn't actually mean a table spoon you eat with. Yes, the official standard tablespoon is probably bigger than most actual table spoons, if that means a spoon you eat with.
In most American kitchens,

The spoons that you would eat with are equivalent to teaspoons. They hold approximately 5ml.

There are larger spoons called tablespoons that are primarily used for serving food from common dishes and called that because they were for “the table”. They hold approximately 15ml.

Personally, I like to use the tablespoons for eating soup.

I just tried to measure my actual eating spoons... I have two sizes in my kitchen, the larger one I think of as a "soup spoon" does seem to maybe be about a tablespoon indeed! I think. I may not have had the best technique to compare, trying to pour water from one to another (also 'almost filled it' can be deceiving depending on the shape of the thing, "almost" could really be ony around 60%).

That the eating spoon is so much shallower than my actual 1 tbsp measuring spoon would make it less convenient to try to use it to measure for a recipe.

I (in the UK) have always understood a tablespoon to mean 10ml, but also that the exact quantity doesn't really matter and I'm ok just to approximate it with an actual tablespoon or according to how I feel.

The Wikipedia page on tablespoons has a lot of (now) unsourced claims about UK tablespoons that make me frown.

I believe every household in Sweden has at least one set of plastic measuring spoons, like these. You'd think they were issued at birth, or something. https://www.pricerunner.se/pl/461-4127639/Koekstillbehoer/No...

They have a 5ml teaspoon (sv: tesked) and a 15ml tablespoon (sv: matsked). Also typically a 1ml "kryddmått" (literally "spice measure"; no idea what the English equivalent would be), and an obviously-100-ml dl (decilitre). Nobody (well, hardly anyone) uses "normal" spoons.

I have a brass set, maybe because I wasn't born in Sweden.
> This is kind of random, but I was watching a cooking video where the presenter said things like "we add two tablespoons of olive oil", and it looks like they pour much more than that.

I don't know which chef you watched but Gordon Ramsey and olive oil is a meme for a reason. He uses way more than the amounts that he mentions. Most tv/youtube chefs eyeball stuff like oil and seasoning anyway, I wouldn't worry too much about it.

I studied classical French cuisine in Europe and when I came back to the states, I found that everything here is measured by volume vs by weight there. The scale is such an integral part of the kitchen. Because it’s drilled into me, I still measure everything by weight.

Otoh, for Indian cooking that I grew up with, it’s always by ratio. Or at least how I learnt it. Example: 1:3 ..rice:water. I guess it’s based on volume but with non standard cups/tbsp etc. For seasoning, you go ‘by the nose’. And taste...taste...taste.

As an aside/off topic slightly: You cook with your senses. For example, one of the earliest kitchen chores my grandmother taught me was to make ghee from churned butter. It’s a thin line between caramelised and burnt. How can you tell? You ‘listen’. When the butter fats are completely caramelised and there is no more moisture content, the top froths and there is no more sizzling sound. So here..when you are in the steam/multiple mingling smells and you can’t see the bottom of the pot of caramelised butter fats...all you have is your hearing. If it becomes silent, then it means it’s done. You can’t make ghee with a timer or thermometer. Tools don’t make the chef.

I used this technique at work when I was cooking professionally. Caramelised butter can be beurre claire(just melted butter..you don’t want it to smell caramelised), beurre noisette(smells like roasted hazelnut), beurre noir(black..as when used with cooking skate etc). I had a counting system after all sounds have stopped to get to the right point of butter melting.

https://en.wikipedia.org/wiki/Tablespoon

The unit of measurement varies by region: a United States tablespoon is approximately 14.8 mL (0.50 US fl oz), a United Kingdom and Canadian tablespoon is exactly 15 mL (0.51 US fl oz), and an Australian tablespoon is 20 mL (0.68 US fl oz). The capacity of the utensil (as opposed to the measurement) is defined by neither law nor custom, and it may or may not significantly approximate the measurement.

I actively will turn away from any recipe that uses units not found in the SI system
well, teaspoon and spoon are basically metric- 5ml and 15ml
No, those are vessals who may or may not have those measurements. If it is supposed to be 5ml of liquid or 15 gr of something then, in my humble opinion, it should be stated in those terms.
I was confused by this too a long time, since i am living in a metric world. Tablespoon and teaspoon are units and you can buy measurement tools for tablespoons, teaspoons and cups.

Weight is far superior as a cooking unit, due to flour compression etc. So if possible use weights :)

Baking is science, cooking is art. Use metric values when baking and intuition when cooking.
> we add two tablespoons of olive oil", and it looks like they pour much more than that

I saw that on cooking shows often, I guess it is cooking by a feel instead of following the exact measurements. For some things it doesn't really matter.