Is Getting Your Coffee Pre-ground Worse Than Grinding Fresh?
- Shortly after grinding coffee loses many of its (wonderful) volatile aromatics.
- You can still enjoy an incredibly delicious cup if coffee is pre-ground but yes, you will be missing some of the flavour potential.
- If pre-ground you also can't control the grind as a variable when dialling-in your brew.
- You can compensate with other brewing variables but grind is a very versatile one to give up.
- Opt for a more expensive hand-grinder over a cheaper electric grinder.
- Always opt for a burr NOT blade grinder.
- If having your coffee pre-ground then ask them to grind coarser than what they usually would for your preferred brewing method.
Transcript (Adam Marley speaking):
Hey, everyone. Welcome back to another tips and tricks with me, Adam. This week's tip is about grinding your coffee if you're going to be brewing it at a later date, not grinding right when you brew. So this is if you're buying whole beans, but you don't have a grinder at home, then you're going to ask either us, if you buy it online, or the cafe partner of ours that you're buying it from to grind it for you.
Now, there's nothing really wrong with this. A lot of people, including myself, do suggest that you maybe look at investing in getting a grinder for home, because then I would probably just, I wouldn't really bother with a hand grinder. I'd probably just save a little bit more and then get an electric grinder because it will make your life so much easier.
And I do recommend this because, if you're not grinding the coffee fresh- There's a couple of issues. If you're not grinding coffee fresh, then one, you're going to lose some of the volatiles. A lot of the volatiles from coffee will leave within a couple of minutes after grinding it. And so if it's being grounded a week ago before you brew it, then you've lost quite a few volatiles already. So some of the more delicate, complex flavors of the coffee gone forever when you grind the coffee, for instance, if you're getting it ground for you in a cafe it smells amazing? Yeah, those smells are, you're smelling them and now they're gone. So they're not going into your brew at home later on. Just something to think about. I used to get a lot of the flavor from the coffee.
The other one is that you won't be able to change your grind on a daily basis to dial the coffee in perfectly. You'll have to, because the whole bag is now ground, what you'll have to do is change your other variables, which is fine. But for me, I like changing grind as the variable that I manipulate to get the extraction perfect, because it's just easier. It's just easier to know what you're going to get and make more finer, more granular adjustments, getting really close to perfect for that extraction. Anyway, that's the reason to get a grinder. That's not the tip. That's just me trying to sell you on getting a grinder, the benefits of that.
But let's just say you don't have a grinder, you're getting your coffee pre-ground. My tip for this week is to always ask for your coffee to be ground coarser than what you would ordinarily grind, or have the coffee ground, for whatever brewing device you're using, if you're going to grind right before brewing. That was a pretty convoluted tip. Let's see if I can simplify that.
So, if you're going to say grind for an AeroPress, this is a random number, I'm not saying grind on this number, but let's just say, for instance, you were grinding on seven, on whichever grinder the cafe uses. They make AeroPresses in the cafe and they go for an AeroPress pre-grind on seven. Now, ask them if, they're not already doing this, and if you're a barista who grinds for people, please, this tip is for you really. But, if you're asking them to grind for you and they usually go, "Oh, yeah, for an AeroPress we'll do it on seven," then I'd suggest them grinding it maybe on nine, if nine is coarser than seven. Usually numbers go up as it gets coarser, but it depends on the grinder.
So you're going to want to go a bit coarser. In terms of how much coarser, it's really hard to say. I mean, I'd probably say maybe 25% coarser. Not in terms of grind size, but in terms of the number on the dial. Again, it depends so much on the grinder. This is why you should have a grinder for home. But you want to grind a little bit coarser than if you were going to be brewing the coffee straight away. Maybe you do have a grinder for home, but you're going to grind a whole bag of coffee to take camping or something like that. Then this is a great example because you know what grind setting you'd ordinarily use for your AeroPress or your plunger or your pour over, then you'd want to grind coarser than that when you grind up the whole bag to take camping, or wherever it might be.
The reason for this is because one of the things that happens when we grind coffee fresh and we brew it is there's a lot of carbon dioxide trapped in the coffee. You grind those beans up, and then the carbon dioxide will evacuate from the ground coffee, and you'll see it when you're brewing coffee, it'll then form a foam, which will stop, and you get this... That's what we talk about the crust on cupping coffees or on a plunger. That crust is a mixture of grounds and foam, of gas, the CO2, when you've added the water to it.
And that CO2, carbon dioxide, will prevent the water from interacting with the coffee. And as a result, it'll reduce the extraction. Now obviously we then break the crust or we then bloom the coffee if we're making a pour over and then we add the rest of the water, that's to remove the carbon dioxide. That's why we do those things. And then after that point, then the coffee can come in contact with the water correctly and extract.
Now, if you don't change any other variable, if you have your coffee pre-ground, I'm going to say most of that carbon dioxide has already left the coffee before you go to brew it. And so what's going to happen is, you're going to have a lot less interference between water and coffee from that carbon dioxide, because most of it has already left the ground coffee. And as a result, if you didn't change anything else, then you're going to have a much higher... Well not much, but you're going to have a higher extraction. I'd say, a high enough extraction that what would have been a really nice brew if you'd ground fresh at that setting would probably be over extracted, bitter, and potentially stringent.
So yeah, I mean, you can change other variables, but for me, I would ask the coffee to be ground coarser to compensate for the lower amount of carbon dioxide which will be in that actual brew when you go to make the coffee. So that's our tip for this week, which I thought was going to be a little bit simpler than it ended up being. Sorry. Hopefully that was all made sense. And one's again, I guess my little bonus tip which actually came first was save up for a grinder for home if you're getting your coffee pre-ground because you definitely enjoy your coffee more. Anyway, thanks for tuning in and we'll see you next time. Bye.