Why do vintage mugs have concave bottoms?

I couldn't find this on TC, although I'm certain somebody must have asked this question before.

But why do some vintage mugs have concave bottoms? I'm sure just about anybody who has vintage mugs have noticed this. And vintage Mr. Bali Hai mugs have versions with both concave and flat bottoms. All of the modern mugs that I have seen have flat bottoms.

Was this a manufacturing issue? Was it a way to allow restaurants to serve smaller portions? Perhaps to strengthen mugs for the constant slamming onto tables by hundreds of customers? They are a real pain in the neck to clean, particularly when one is found in the wild that 35 years worth of accumulated grime.

Excellent question - I always thought it was for strength (as in a champagne bottle). Mr. Bali Hai is a pretty big mug, so I doubt it was concaved to reduce the amount of booze used - that's what ice is for!

my thought, workmanship or quality, then and now.

There are still many glasses, etc. today that have a large concave bottom. I think it is simply to control the amount of liquid it holds. Most glasses are meant to hold an 8 ounce cocktail. A large tiki mug, with a flat bottom, might end up as an 11 ounce mug. I won't say it is to cheat you, but it is to make sure you don't think you are cheated. If I serve you an 8 ounce drink in a 10 ounce mug, you will complain.

Swank Blather- Talkin' atcha

[ Edited by: Swanky 2006-11-07 09:26 ]

vintage Mr. Bali Hai mug came to mind too, but their has to be others to have the claim that vintage has the bottom. I don't have really any vintage mugs, so what are some the the others that have this bottom.

I do know that a flat bottom cup or bowl will scrape table surfaces more if they are flat but bowls with rings (convect) get their strength. The load barring weight is applied the where the bowl starts its angle up.

The black Moai mug comes to mind as having a big concave bottom. Even the "flat" ones are usually not flat, but have a ring they sit on. The Daga mugs are an exception.

Next time you get a mug of beer, notice the huge opening in the bottom.

If it were a strength of structure thing there would be more like that than flat. Thickness has more to do with keeping a mug from breaking than that I am sure.

As a side note. A glass full of crushed ice holds significantly less liquid than one filled with cubed ice. This too can allow a drink that is less ounces look like a bigger drink in the glass...

Swank Blather- Talkin' atcha

[ Edited by: Swanky 2006-11-07 09:26 ]

I'm in agreement that it's for strength, because if a glass or ceramic mug gets hot from washing, and you put ice in it, the bottom may weaken and bust. I've seen this happen with cheap glassware.

I was speaking with " makedamug" yesterday. He said it was more to make a lager mug hold less of a drink. The bar needs to try to keep the price with in reach of the customer. Makes sence to me.

It's a practical glazing issue mostly.

The entire mug is dipped in glaze after it's fired the first time (bisque). If the bottom is flat, the glaze must be completely wiped off or the mug must be put on little "stilts" so it doesn't fuse to the kiln shelf.

If the bottom is indented, a quick wipe leaves only the center glazed. This also allows the addition of incised logos, decals, etc.

see there ya go! Squid is so smart right on brah!! but ... why don't they make them that way anymore??,,,, light up, contemplate this a while..... 8)

On 2006-11-07 23:36, Hiphipahula wrote:
but ... why don't they make them that way anymore??,,,,

Well Hipster, if you check your Tiki Farm mugs, they're all like that. Not as drastic of an indent as some vintage mugs but if I didn't put it there, Holden's factory would have my head. (could that be a mug? Severed Squid Skull?) Yikes!

Some manufacturers have no problem with the additional labor to stilt the mugs but you can't get any decent markings on the bottom that way.

On 2006-11-07 23:36, Hiphipahula wrote:
see there ya go! Squid is so smart right on brah!! but ... why don't they make them that way anymore??,,,, light up, contemplate this a while..... 8)

The deep concave is only needed for mugs that are used in a bar. If it's a mug for collectors, they don't care how much liquid it holds. A restaurant will demand that the mug hold a certain number of ounces. So, a concave bottom is required only to compensate for a mug design that would hold too many ounces for what goes in it. If you have a bar and you give a design for a Mai Tai mug to Holden and squid sculpts the design and we find that it holds 11 ounces, you have him put a concave bottom on it so that it only holds 8 ounces.

Yup, Swanky's right too. It all figures in.

Well Hipster, if you check your Tiki Farm mugs, they're all like that. Not as drastic of an indent as some vintage mugs but if I didn't put it there, Holden's factory would have my head. (could that be a mug? Severed Squid Skull?) Yikes!

Under the New decanter thread for dirty donny, I gave a suggestion for squid lid, so slap the two together and its Severed Squid Lid. What do I win?

I have the Mr. Bali Hai Mug (vintage) and one has a concave bottom and the other is flat. Not sure if this substantiates the theory, or not, but it seemed like poor old Mr. Bali was getting singled out!

On 2006-11-08 10:47, net-tiki wrote:

Under the New decanter thread for dirty donny, I gave a suggestion for squid lid, so slap the two together and its Severed Squid Lid. What do I win?

If Holden puts MY name on DONNY's mug, you win the 5 bucks that Little Lost Tiki owes me! In any case, I know what I'm calling my next hat...minus the "severed" part.

On 2006-11-13 22:07, squid wrote:

In any case, I know what I'm calling my
next hat...minus the "severed" part.

Will it look like THIS:

http://www.cafepress.com/buy/squid/-/pv_design_prod/pg_3/p_storeid.26329566/pNo_26329566/id_7971802/opt_/fpt___aP______a_____a______D/c_0/

OR THIS:

http://www.cafepress.com/buy/squid/-/pv_design_prod/pg_1/p_storeid.44745536/pNo_44745536/id_10703452/opt_/fpt___aP______a_____a______D/c_0/

OR THIS:

http://www.cafepress.com/buy/squid/-/pv_design_prod/pg_4/p_storeid.51103929/pNo_51103929/id_11586228/opt_/fpt___aP______a_____a______D/c_0/

Inquiring minds want to know.