So I came across the first stone in my beans today. Fortunately I saw it as I was weighing out into my dosing cup - made me thankful I'm using a single dosing grinder as if I had a hopper-fed grinder I doubt I'd have seen it. Was wondering how common is it to find stones in your beans? This is the first I've had in 2 years. [URL=https://i.imgur.com/9IGNutp.jpg][IMG]https://i.imgur.com/9IGNutp.jpg[/IMG][/URL]

Don't think it's overly common. I've not had a stone in my beans since I started the habit about 12 years ago.

Never seen one so far, although I always quickly check the weighed beans for an unknown object before chucking the beans in the grinder!

i have had stone(s) in my beans in two different occasions so far. Let your roaster know about it. i was also lucky as i was single dosing and spotted them before grinding.

I expect you’ll find DCs article on this from 15 years-ish ago if you look on the old wiki

They are more common with some origins and processes than other - e.g patio dried natural.

Why you should always check your dose before firing it into the grinder. Roasters have kit to filter out foreign debris but some inevitably gets through. Over the years, have had three occasions when a small piece has popped up in the dosing cup. As @"Rob1"#171 says, it's almost always confined to patio dried naturals.

Had one today, that too on a day I couldn’t be asked to check. Weighed 18, skipped the practice of not checking the weighed beans, chucked them in and got jammed a half-way through. First time, I thought must be one of the odd beans playing a trick. I continued to grind; as soon as it happened the second time, I dumped the unground beans on a plate to find a small stone. * The burrs look fine after removing and examining the set closely. * A few scuff marks in the chamber Bottom line - Lessons learnt. Will let Foundry know for their information, though. [URL=https://i.imgur.com/0MYOVEk.jpg][IMG]https://i.imgur.com/0MYOVEk.jpg[/IMG][/URL]

Stones in Beans

Dusk

Useful to know, I hope that the plate I use to weigh my beans spreads them out enough to make any foreign objects noticeable but I don’t actively check for stones.

LMSC

Dusk I use a small dessert cup. The stones aren’t visible. I take a small handful at a time, check and chuck them all in.

DavecUK

Dusk I don’t actively check for stones.

Something you should always do. I remember giving this advice almost 18 years ago and someone told me off for giving such advice, stating, Speciality coffee doesn’t have stones! Which is nonsensical.

MediumRoastSteam

DavecUK Something you should always do

And even more so if you buy greens and roast your own.

If memory serves me right I have found a stone once on greens. Never on roasted coffee though, so far! 🤞

DavecUK

More roasters need to invest in destoners….

LMSC

DavecUK I did advise Foundry. They came back and advised checking the dosed beans quickly is required. They said it’s rare they find smaller debris but impossible to guarantee.

DavecUK

LMSC The size foundry are they should absolutely have a destoner…it’s not a 100% guarantee, but helps enormously.

LMSC

DavecUK That’s why they are probably confident stones are very rare in their bags.

james65477564

I encountered a stone about 10 years ago with my then 3 month old vario. I couldnt see anything wrong with it after, but the grinder never worked properly again; I think the plastic burr carrier got distorted in some way

JonWoo187

I source quality green from very good online sellers here in the U.S. and yes pieces of stone, concrete, etc. do pop up now and then. From the time I weigh the green to actually using the roasted coffee I look at/handle that coffee 6-7 times to be sure nothing odd makes it into my grinder. Might seem like overkill, but it’s quite easy to overlook things that blend in so well at times.

Dusk

Found my first ever stone today, I don’t actively look for them but I weigh my beans on the plastic tray that came with my scales. Fortunately it spreads them out so the stone was quite obvious and I caught it before grinding

drdre89

Dusk ground up stone brings a nice “earthy” flavour to the cup.

JonWoo187

Dusk Whoa… that toasted coffee is likely nearly as dense as the stone, bwahaha

Inspector

drdre89 yea, and metal chippings from burrs would give a nice mild acidity.

delta76

dutchy101

never seen one. I believe stone is a no -no for specialty coffee. i.e. if a stone is found the batch will be disqualified as specialty

MWJB

delta76 Unfortunately, that is not true at all.

delta76

MWJB

right, I remember it incorrectly. One large stone or up to 4 medium stones per 300gr is “acceptable”

Annex 7: Green Coffee Classification and Grading (fao.org)

Dusk

It must surely be almost impossible to remove the chance of any stones and surely speciality coffee is likely to come from smaller producers and through smaller processing plants that might not have the capabilities of big producers (for example Illy or Lavazza).