Should You Use Scales When Making Coffee?


Should You Use Scales When Making Coffee?

  • Short answer: yes! Always.
  • If you're not measuring by volume or weight your results will be inconsistent as the ratio of coffee to water affects strength and extraction.
  • Volume has several flaws that weight mitigates.
  • Different beans and roasts will have a different weight for the same volume (due to density differences).
  • The bloom that occurs when adding water obscures how many ml of water have been added.
  • The affect of the bloom changes with age off roast (even for the same bag of beans).
  • Scales allow you to know exactly which variable you're changing and by how much - enabling you to dial-in coffees quickly and brew consistently.

Transcript (Speaker: Adam Marley)

Hey, everyone. So it's time for another tips and tricks video. For this one, I actually wanted to harken back to our very first tips and tricks video in this series which my tip was to always use scales when brewing coffee. For this tip, I wanted to go back and explain why, and why not using scales can sometimes lead to frustration when you're trying to dial in a coffee, when you're just trying to get the best brew you can out of a coffee and have the best experience.

So the reason we use scales as opposed to not using scales is because with scales, we're looking at the weight of the coffee and the weight then gives us an accurate reflection of the mass of the coffee. If we don't use scales and instead we just rely on what we in the industry usually call volumetric measurements, so we're looking at the volume of it, how much space the coffee or water or whatever it is is taking up, and particularly if we're just eyeballing that, but even if we're using a measuring jug or some sort of measuring ability, it's going to be very inconsistent. Why? Why is it going to be inconsistent?

So there's three times that this crops up when you're trying to brew coffee. The first two are with espresso, and then the last one, I mentioned, will be for specifically a filter coffee and certain styles of filter coffee. So the first one, I guess actually it's for any kind of coffee, but for any cup brewing of coffee, espresso or filter, the first one is with the beans themselves or the ground coffee itself. If we weigh the coffee, then we know exactly how many grams we're getting, exactly how much mass of ground coffee we have to extract from, and that's to say if we want an espresso, we've got 20 grams or for a filter coffee, you might be using 30 grams, whatever it is, depending on the size of the filter you're brewing or the size of the espresso basket, the basket you're using to brew your coffee is and what size of espresso you want.

It doesn't matter, those specific numbers are irrelevant, but we know exactly how much coffee we're using. So first of all, every single time, if we want to be using the same amount, we can, and if we want to change things, we know exactly how much we're changing things by. Now, if we do it with volume, say for espresso, the thing that everyone used to do that I got taught to do many years ago when I was being taught how to make espresso was you just fill the portafilter, the basket, up to the top.

You might then scoop a little bit out or something like that and you go, "Oh, well, if I'm filling it up to the top every single time," or if say you're brewing filter coffee and you're using a scoop and you go, "Oh, okay, I'm using three scoops of coffee every time I make a plunger," whatever it might be, that's all well and good and that scoop and that portafilter is going to be a pretty accurate reflection of the same volume.

However, coffee beans, and ground coffee from those beans have a very different density origin to origin and roast level to roast level. So what it means is if you're using that volumetric measurement and you swap from one origin to another origin, you will probably have a very different amount of actual coffee solids that you're going to be extracting from. And if you swap roast levels, it's even more pronounced. So if you go from a medium roast, so for instance, just to be very specific, but you can generalize this, a lighter roast coffee, you'll have a lot more coffee in that portafilter for espresso than you for a darker roast.

So if you swap from a dark roast to a light roast, all of a sudden you've just started using quite a substantial amount more coffee in terms of mass than you were previously if you're not weighing it. It takes up a lot less volume. The darker you roast the coffee, the less dense it becomes, and so you have less coffee in the same amount of space. So that might not sound like too much of an issue, but it's going to lead to inconsistencies particularly with dial in for two reasons. One, less coffee or more coffee means weaker or stronger, right? So the strength of your coffee that you've brewed will be different time to time when you make those changes which is not ideal, unless you just want to mix it up and you don't know what you're going to get, and that's fun. It wouldn't be for me.

The other thing is that the amount of coffee you're using relative to the amount of water you are brewing with has a big impact on the flavor of the coffee you get at the end. We call that the ratio, we call that the ratio of coffee to water. Sometimes recipe will include other things as well, but yeah, so that's the ratio. So if all of a sudden you're using more grounded coffee, but the same amount of water you were using previously, then you're going to have a less extracted shot than you did previously. So you can see why it's going to lead to some inconsistencies and potentially make it very frustrating when you're trying to get the best out of a coffee. So that's both for espresso and filter coffee.

I might actually start, the next one is not to do with the coffee, but to do with the water, might start with that one for filter. So when you're brewing a filter coffee, let's just say it's most obvious when you're doing a plunger, so let's just say you're making a plunger and you've got your ground coffee in the bottom and then you pour your boiling water over the top vigorously to get everything nice and saturated which you should be doing. If you're not weighing it, you're going to stop adding water to that brew when it gets to the right height. You're going to go up to a certain height in the plunger every single time.

However, that's not going to be the same amount of water every single time because when the coffee grounds come in contact with water, they bloom. We call it blooming and that's just the carbon dioxide in the coffee escaping. That bloom, you would've noticed it if you brew filtered coffee, that bloom creates this crust on top with coffee grounds and those coffee grounds are being suspended with gas bubbles all around them, carbon dioxide. The size of that bloom is determined based on many things, but particularly not just on origin and roast level which are very important roast level, particularly will have a big impact just like we were talking about before.

However, the age of the coffee will have a massive impact on the bloom as well. So you haven't even changed anything. You're not using a different coffee, you're not using a different roast. But if you're not weighing the water you're pouring into your plunger, you are going to get a different amount of water each time because as the coffee ages, it has less carbon dioxide and the bloom will be a much smaller. So you'll find if you're not weighing it as the coffee is in your kitchen and using it over the week or the fortnight, as the coffee's been sitting there longer, you'll start adding, if you're not weighing, more and more water each time you brew a French press.

And so going to have two effects. If you don't change anything else, it's going to make the coffee weaker, and it's going to extract higher than before, potentially over extract the coffee. When you're brewing coffee, if you don't weigh, if you've ever noticed, you think to yourself, "Oh, the coffee tastes really good at this time of roast," this might be why. There's other impacts as well, there's other reasons that coffee will taste different as it ages. But if you're not weighing, I'd say this is 90% of what's going on there probably.

So if you want to remove that variability and have the entire within normal frame within a couple of months of drinking that coffee, then to have that be consistent, well then, yeah, get yourself some scales. Going back to espresso now. So the other thing, we're relying on volumetric measurements as opposed to weight, the other thing that can have an impact on how you dial in and inconsistencies is, and this is again how I was taught to make espresso, you're pouring an espresso, maybe you fill the coffee up to the top of the basket, that's consistent, volumetric but not in weight, and then for the shot, you're a good barista. You're a good home barista, a good professional barista, you're paying attention so you have a shot glass and that shot glass has incremental measurements telling you exactly how much coffee is in there in theory.

So you might have a shot glass and it will say like 15, 30, 45 mLs, whatever it is, and you might go, "Okay, every single time I pull my shot, I make sure to pull it to 30 mLs," say, and you're like, "I'm being consistent." That's great. It's 30 mLs every single time, but it's not. It mean it is, it's 30 mLs, but it's not going to be the same amount of water and thus espresso, now it's been brewed every single time because that CO2 that we just mentioned, that's in the espresso as well, and the crema is formed by the CO2.

So in the same way that that foam on top of a French press, on top of a plunger is caused by carbon dioxide, the crema is as well. And so as the coffee ages, you get less and less crema and also roast level, and other things have an impact on the amount of crema as well. But just to illustrate how important scales are, even if you're not changing anything about the coffee other than it's aging, which is going to happen, the crema is going to be less each time.

So if you think about it, part of that volume in that shot glass part of it at the top, that's crema. That's just gas. That's not espresso. That's just gas and you'll notice if you leave it to sit long enough for the gas to leave and the crema to break down, you'll be in a much lower line than you were previously. So if you're pouring to 30 mLs in your shot glass when the coffee's very fresh, that's going to be a lot less espresso, a lot less water liquid out than a couple of weeks later when you're brewing that same coffee, or even a few days later, it'll have a strong impact pretty quickly, which again means not only is your strength going to be varied, but particularly for espresso which is very sensitive to small changes in the recipe, you'll probably have a very different extraction.

You haven't done anything. You've tried to be as consistent as possible, but through no fault of your own other than not weighing, you're going to have an inconsistent result because that crema is basically the crema, the foam on top of French presses, the different densities in coffee beans and ground coffees, that basically means it's almost impossible to be accurate and consistent with a volumetric measurement in that sense of the word. There's other times you use that word, but we're not talking about that today, we're just talking about not using scales when you're brewing coffee.

So if anyone was curious for the why from our very first video, and if you want, you can go back and watch that if you checked it out, which this is kind of reiterating that point and you might think I'm nagging you a little bit now, but it's so you have a better experience drinking coffee, that's why I'm nagging you. Anyway. I'll see you soon, guys. Thanks.