Do certain glazes effect the tase and smell of coffee?

[Kimberly Young]

Hi, I have had a couple of customers that say their coffee mugs smell funny, icky, and effect the taste of their coffee. I use porcelain and fire to cone 10.  Could it be the glaze is slightly underfired?

How do I suggest to them to remove the smell/strange taste? I recommend that they wash the mugs in the dishwasher at a normal or high heat to make sure they are properly washed. 
 

any other suggestions? Soak them in vinegar? Replace the mug with a new one? 
 

thanks in advance -

Kimberly 

[Bill Kielb]

4 minutes ago, Kimberly Young said:

any other suggestions? Soak them in vinegar? Replace the mug with a new one? 

Glaze recipe? Any pictures? Cups that smell are not a good sign the glaze is durable.

[Babs]

Well i bet the mugs are needing a good wash!

How many mugs have youmade and sold using this glaze?

A friend got cross if sone used her tea mug for coffee. She said ot made thetea taste funny if anyone did that.  Another person told hher to wash her mugs properly. A brave soul, but it seemed to do the trick....

[Sorcery]

Maybe someone is so excited to drink from a handmade mug they are screwing up the brewing!

Sorce

[liambesaw]

I've only seen this with absorbent clay or metallic glazes.  

[neilestrick]

3 hours ago, liambesaw said:

I've only seen this with absorbent clay or metallic glazes.  

Yep. I'm betting copper leaching. There's no reason a mug should affect the taste of the beverage unless it's leaching metals or harboring nastiness.

@Kimberly Young post the glaze recipe.

[liambesaw]

Yep, metal ions are pretty gross tasting and basically turn your morning coffee into a battery that zaps your mouth with electrons.

[Callie Beller Diesel]

Just because a recipe fires to cone ten doesn't mean it won't leach. Oribe and shino recipes can be suspect if they're not properly balanced, and they're not the only ones. Glazes need to be tested for durability before you try selling them, imo. If you are getting reports from more than one household that the glaze is giving the coffee a "taste," I would not waste a lot of time on suggesting washing is the problem to your customers. I'd offer them an apology, and either a refund or an exchange for a mug with a liner you know is more suitable. I would also take the extra step of reaching out to anyone you'd sold a similar mug to, and offer them the same. Some people won't make the complaint to you, but they will to their friends and family, which is never good. If they take the exchange, I might even add a small extra item (ring dish, ornament, spoon rest) as a thank you for their patience and understanding. It can turn an embarrassing mistake by a newbie into a positive customer service experience from a conscientious and professional craftsperson ;).

If you have indeed done your due diligence and you're sure it's the customer not washing their wares properly, a combination of baking soda and boiling water works much better than vinegar. Put a tablespoon or so of baking soda in the mug, place it in the sink and fill with boiling water. It will fizz, so don't do this on the counter. After the water cools to the point where it's easily handled, the stains should wipe out easily with a cloth. I live in an area of very hard water, and it works a treat.