From Kev @ coffeeblog. Do This One Thing: Dose Volume.

Hello   Kev here :-), In today's edition of brew time, I'm introducing the first of a new series of short email guides, called "do this one thing" in which I'll introduce really quick and simple things you can do to increase the quality of your coffee.  Do This One Thing... Focus on dose volume, not purely dose weight.  The "dose" refers to how much ground coffee is loaded into the basket. If you're using a traditional espresso machine with a portafilter (you can ignore this if you're using a bean to cup machine) you'll be familiar with dosing by weight, for example grinding 18g of coffee into the basket.  By the way, if you don't yet have an espresso machine but you're considering investing in one, see: Best Home Espresso Machines What is dose volume? It's the amount of ground coffee in the portafilter, not by weight but by volume, in other words how much space in the basket is taken up by the coffee.   In the image above of the tamper on top of the coffee in the basket, if the dose volume was bigger, the tamper would be sticking out further, if the volume was smaller, the tamper would be further into the basket. Let me explain why dose volume is more important than dose weight. Headspace Headspace is the gap above the puck of coffee under the shower screen above, and this is gap is where the pressure builds up. If you over fill the basket and end up with too small a headspace, this is referred to as overdosing, and it can cause issues with extraction.  Having too big a headspace by dosing too small a volume wouldn't usually cause any negative issue other than sometimes resulting in a sloppy puck, but also having a shorter dose in a basket will usually require a change to the grind size. If you dose by weight and pay no attention to volume, the volume will change at the exact same weight, based on the beans you're using (the varietal and the roast profile) and the grind size.  Consistent Volume is More Important to Extraction Than Consistent Weight If you do what most people do, you'll have a consistent dose weight and an inconsistent dose volume while you're dialing in. If you're adjusting your grind finer, the volume will be shrinking (the headspace will be increasing), if you're adjusting coarser the volume will be increasing (headspace will be decreasing).  This is one of the reasons that dialling in can be confusing, because you potentially have two variables working against each other.  I recommend weighing the dose too, because this allows you to ensure a consistent brew ratio too, (for example if you're using a 1:2 ratio and your dose weight is 19g then you'd be looking to pull 38ml of espresso). But while dose weight is important to the ratio, it's volume that is important to extraction, so I'd highly recommend not focusing purely on dose weight, but to also take volume into account. How to do this? Very simply, if you have a Sage machine that comes with the razor tool, use the razor tool, as this is what it's designed for. Best Sage Coffee Machines If you're one of the many people who didn't immediately see the point of this tool, and threw it into the back of a cupboard, I'd definitely recommend digging it out. If you have the Sage bambino, it doesn't come with the razor too, but you can buy them from Sage for about £7. Most of the time, when you're about dialled in, you'll probably find that you have 18-19g of coffee in a 54mm Sage basket after tamping and trimming with the razor tool. If you don't have a sage machine, just try to keep an eye on where the tamper usually sits in relation to the rim of the basket, and use that as an indication of whether you may be over dosed.  There is a test you can do to check if you're over dosing, which is to put a penny (or if you want to be a bit more hygienic, a thin washer) on the top of the coffee after tamping, and if there's a penny or washer shaped indentation when you remove the portafilter, that's a sign that you've over dosed the basket. This is one of the great things about the Sage Barista Express Impress, as this machine automatically ensures that the dose volume is correct with every shot.  Not only does the Impress have a tamp lever which applies an exact 10kg tamp every time (with virtually no effort from the user, you'll be able to tamp using one or two fingers) it also measures the dose volume, and guides you to achieving the right volume each time.  The really, really clever part, is that the machine learns. So once it has guided you to get the right volumetric dose (via a sensor) it remembers how long, in total, it needs to grind for in order to achieve that volume each time going forward.  You'll need to re-do the dose part each time you swap beans, but it's very quick and easy to do.    Sage Barista Express Impress Review Sage already have some of their Black Friday offers in place and I have a discount code that gives you an additional 15% off the already discounted price: See prices at Sage and use code VirtualDemoUK-lEqKg7U0AU for an extra 15% off There you go, in a nutshell for the first "do this one thing" guide, think of the dose in volume not purely in weight but also think of the dose in volume, so keep headspace in mind - and the easiest way to do this if you do have a Sage machine, is to find the razor tool and use this. I hope you enjoyed this edition of Brew Time, and I'll see you next week :-).  Thanks again, Kev coffeeblog.co.uk cworks.co.uk Follow me on Twitter Follow me on Instagram Follow me on Facebook Subscribe to my YouTube Channel Become an Accredited Coffee Botherer

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