Contact & FAQs

If you have any questions about our grinders then take a look through these FAQs


The Aergrind is compact, holds about 30g of beans and has 38mm titanium nitrided burrs. It's our quality portable compact grinder.

The Feldgrind is our all-round grinder. 38mm titanium burrs but with a bigger capacity and longer shaft means this will be a more durable grinder than the Aergrind but slimmer and more portable than the Feld47.

The Feld47 is larger, with 47mm titanium burrs offering more controlled adjustment than the Aergrind and Feldgrind and is great for dialling in espresso. It holds about 47g of beans.

Whilst the Aergrind and Feldgrind can produce a very competent espresso for almost all standard domestic machines, accepted wisdom holds that bigger burrs produce better results for espresso and generally more uniform grinds. If you are especially focused on espresso, please consider buying the Feld47 to get the best results from your equipment.

A basic brushing every now and then depending on usage should be sufficient - a broad tipped, long handled artist's brush or narrow toothbrush would be suitable. Occasionally wiping with a barely damp cloth is all that is required for the outer body of the grinder. A quick grind of a few grams of uncooked rice can be used to clean the burrs if they have not been used for a while. Please store in a dry place in general but particularly if you do not intend to use the grinder on a daily basis. Full cleaning instructions can be found here.

If something is out of stock, add your email to the 'out of stock' box and you'll be notified the minute we restock. You can also sign up to our mailing list and you'll be notified about new products, offers and flash sales too.

In Scotland you never water another person's whisky, and at Knock we never dictate someone's grind settings!

But seriously, the bean varietal, roast style, roast age, brew method and even water type all play such a huge part that its impossible for us to recommend specifics. Your best bet is to test a small grind of a few grams at the appropriate setting from above and see how that compares to your usual grind, then adjust accordingly.

Have a look at our grind settings and instructions page to help you get started.

Yes! For instructions and 'how to' videos, see our Grinder Instructions page.

We offer a 12 month back-to-base UK warranty on all our products. Go to our Shipping & Returns page for more information.

We set the zero point (and thereby the dial numbering) for all grinders where the burrs are "flush" with each other. At this point no grinds can pass through the burrs and whilst it may be possible to rotate the inner burr it is in constant contact with the outer. At this point the crank arm indicator will show between 12 and 1 on the dial, depending on how close you have it to flush.

From here it is important to understand that each burr pairing is genuinely unique and as such it is possible to continue winding back past 12 and "overlock" the burrs - this is where the inner burr passes up inside the outer burr to some degree.

We don't recommend winding the burr in any further than flush as there is a potential to force the burrs into a full lock, where the burrs bind into each other. This can damage the burrs and cause problems with the mechanism. Nothing is to be gained by forcing the burrs together!

To achieve a true infinite adjustment we don't use the limited adjustability of a locking or click stop system - instead we use a friction system, where o-rings provide the necessary stopping power. This infinite adjustment capability is what gives you the ability to really dial in your grind to achieve the best results in the cup.

Your grinder comes with a spare set of o-rings which you should keep safe for if or when your grinder setting start to move.

NB Aergrind mileage - You may find that you if you are an "Aergrind power user" (and more so if you favour very light roasts) that your o-ring needs replacing before the first year of use is complete. This is perfectly normal and just means you have been an above average enthusiastic grinder of quality craft roasted coffee beans instead of soft, volume run supermarket roasts.

We don't regard this as a a flaw in your grinder or necessarily a reason to return the item - it's simply a maintenance requirement of your mileage.

However, if you get through the replacement set of o-rings in under 6 months you should contact us and we can discuss getting you some more replacement o-rings and or trading up to a heavier duty model.

Yes, we sell spare o-rings, rubber bands, crank arms and lids for the Aergrind, Feldgrind and Feld 47 grinders. There's a spares page for each grinder which you'll find in the Grind section of the website. If you have an older model Feldgrind, Feldwood or the original Hausgrind please fill in the contact form and we will help as best we can.


To enquire about your order, please email or complete the form below and someone will get back to you as soon as possible.