The Problems with Paddle (Doser) Coffee Grinders vs On-Demand

In this article and accompanying video, we’re going to lay our cards on the table when it comes to coffee grinders. Specifically, we’ll take a head-to-head look at two different approaches to coffee grinder design: Paddle vs On-Demand. Now, being upfront about our potential biases, we only sell on-demand coffee grinders. We aren’t fans of paddle grinders, and we’re going to explain exactly why in this article.

That being said, we’re not going to try and convince you that you absolutely NEED any kind of coffee grinder, and we won’t mention any particular models either. Instead, we simply want you to be educated on the topic so that you can continue on your journey with as much information as possible. And hey, if you get to the end of this article and are still sold on the idea of a paddle grinder, more power to you.

What is an On-Demand Coffee Grinder?

An on-demand coffee grinder is one that grinds exactly the right amount (or near enough) of coffee for every shot of espresso, right before you lock the grounds into the espresso machine and brew.

On-demand grinders can take many forms, most commonly grind-by-time grinders that use a hopper full of coffee beans and a set amount of time to grind just enough coffee for each shot. Consistency in the exact weight of coffee from a grind-by-time grinder varies between grinders and manufacturers, which is why you’ll often see baristas using a set of weighing scales to maintain consistency, though modern grinders are getting very accurate in this regard.

On-demand grinders can also be grind-by-weight, operating similarly to grind-by-time but with a built-in set of scales that guarantees a fixed gram dose of coffee e.g. 18 grams every time. And finally, you have single-dosing grinders which I guess are technically a form of ‘on-demand’ grinding, but requires the user to weigh the amount of coffee needed before pouring the beans into a small hopper and grinding.

The Differences Between Paddle and On-Demand Coffee Grinders

On-demand grinders are increasingly replacing paddle-shift coffee grinders in this modern age of specialty coffee, and for good reason. Paddle-shift grinders are a product of the coffee industry from years past, making use of dark roasts and being ignorant of the effect that grind size, dose and freshness of coffee grounds has on flavour.

In the 21^st Century, coffee has progressed from a dark and bitter cup of caffeine into a delicious drink with a vast range of flavours. The industry has progressed towards using lighter roasts in general, which require consistent dosing, dialled grind sizes and freshly ground coffee to get the best flavour. Paddle grinders were not created with these requirements in mind, and the industry has moved towards on-demand grinders that are more consistent in dosing, less wasteful and easier to dial-in.

Problems with Paddle Coffee Grinders

Paddle coffee grinders dispense around 200-300 grams of ground coffee into the front chamber at any one time, which is then tapped out using the paddle into the portafilter below throughout the day. In comparison to grinding the exact amount needed prior to every espresso shot, this produces a few key issues:

Freshness

Grinding a large amount of coffee at once and then using it slowly throughout the day decreases the freshness of the coffee, leading to at best a loss in flavour, and at worst a staling of the coffee creating new undesirable flavours.

Dosage

A delicious cup of coffee requires the use of a consistent recipe that outlines the ground coffee dose, espresso ratio and extraction time. For example 18 grams of coffee, 36grams of espresso in 28 seconds. Paddle grinders are inherently inconsistent in the amount of coffee they dispense into the portafilter, though this can be rectified by using a set of weighing scales.

Waste Coffee

Dialling in the grind size of a coffee is one of the most important steps for a café first thing in the morning. With the potential for a barista to grind up to 300 grams of coffee at once at the wrong grind size, they may have to choose between serving 300 grams worth of low-quality coffee drinks or putting those grounds into wastage.

In Defence of the Paddle Coffee Grinder

Going back to before the modern specialty wave of coffee, paddle grinders were very much the industry standard. Whilst the bar has continually risen along with the knowledge on the impact of grind size, dose and freshness, that’s not to say paddle grinders can not make good coffee. When grind size is properly dialled in by an experienced user with barista training, or who is knowledgable of the brewing fundamentals, a paddle grinder can certainly still make good coffee. Paired with a weighing scale to combat the issues in inconsistent dosing, tasty coffee is achievable. Paddle grinders are also very commonly found on the used market, so someone looking to save on their upfront costs may look to a used paddle grinder for an affordable alternative to the modern commercial grinders.

However, keeping in mind the issues in workflow, wastage and freshness, along with the fact that modern coffee grinders are not that much more expensive, paddle grinders are somewhat difficult to recommend.