Sorry, fixing other problems all day long at this end.
There's no emergency here because you don't have to act quickly. If the stain is dry, you can still remove it.
Whatever you do, if you have hard water, it would be dangerous to use hard water to rinse out this stain.
I Google'd "coffee spotter solution" and found this web site advertising that they sell a stain remover made specifically for coffee and tea stains: (scroll down until you see their "Coffee and Tea Stain Remover".
Spotting Solutions Products
If you click on the "View MSDS Sheet" link for their "Coffee and Tea Stain Remover, the PDF file you download says that it contains 2% to 5% hydrogen peroxide.
COMPONENT LIST - SECTION I
COMPONENT---------- REG#------ %
Hydrogen Peroxide-- 7722-84-1--- 2-5
And, later on in that same MSDS sheet (Section II - Physical Properties), it says that it's percent volatiles by weight is 100%.
PHYSICAL PROPERTIES - SECTION II
APPEARANCE: Clear liquid with little odor
pH: 6 - 7
VOLATILE (% WT): 100
That means that it evaporates completely without leaving a residue. Both water and hydrogen peroxide evaporate completely without leaving a residue. So, most likely, that's all that's in this product; it's a solution of 3% hydrogen peroxide in water, exactly the same as you can buy from any pharmacy for 1/4 the cost or so. If it contained any detergents or enzymes, those wouldn't evaporate, and it's % volatility would be slightly less than 100% as there would be a residue left behind after all the volatiles evaporated.
So, if you have any hydrogen peroxide, apply that to the stain and be ready to lift the soiled hydrogen peroxide out of the carpet and apply clean rinse water. If you have hard water, then rinse clean with DISTILLED water. Do not use hard water on a coffee or tea stain.
If you want to know how to remove stains from a carpet using a wet/dry vaccuum cleaner and a spotting solution, read my last post in the thread entitled "How to clean a toilet well".
The reason why I say to use distilled water instead of hard water is because hard water will contain a lot of iron ions. Coffee and tea are "tannin stains". Tannin, or tannic acid is a brown chemical, and it's what makes coffee and tea (and many woods a yellow, reddish or brown colour). Iron ions will react with the tannin of the stain to produce a black chemical called "Iron gall ink", which was used as a writing ink in Medieval Europe for hundreds of years. Iron gall ink is very permanent, so applying hard water to this stain could will result in a dark permanant stain on the carpet.
So, basically the game plan is to either go to a janitorial supply store and buy a coffee and tea stain remover and use it as per the directions, or to just phone any janitorial supply store and ask them to give you the directions on their coffee and stain remover and use those directions along with 3% hydrogen peroxide from a pharmacy to remove the stain. That should remove the discolouration. If the area remains kinda sticky and gets dirty quickly, it's because of the fat and protein in the cream that was in the spilled coffee, and that can be removed later with dish washing detergent and a laundry pre-spray, respectively.
Spotting Solutions Improves Coffee And Tea Stain Remover - Flooring News and Information
The improvement here is almost certainly that they've added a detergent and a precleaning enzyme to their coffee and tea stain remover.
An "enzyme" is nothing more than a protein that breaks down other proteins. Since the cream in coffee contains a lot of fat and protein, "improving" their formulation almost certainly is just adding some enzyme and detergent to it to do a better job removing the milk or cream within the coffee that got spilled on the carpet. The enzyme breaks down the proteins in the cream or milk into small pieces making them more readily soluble in water, and the detergent removes the residual fat from the milk or cream that will still be sticking to the carpet pile. You can use either "Shout" or "Spray and Wash" on your carpet to break down the proteins, and you can use diluted dish washing detergent to remove the residual fat from the carpet (or any detergent or soap for that matter).
Let me know how the hydrogen peroxide works out for you.