Comments to this answer say e.g.,
Can't stress enough how ... important it is to drink more than just water
... (and other people's comments then ask for details about the drink's contents).
The context is in answer to this question, How to ride when the weather is hot? -- to which people answer that it's no longer adequate to just drink water.
There's a related question here Formula for Homemade sports drinks but I don't find it informative.
My question is, what's the minimum ingredient list for a "sports drink", on a day when you should be drinking several liters?
For example, when I get home I drink water mixed with a cheap fruit syrup (i.e. some kind of sugar) plus table salt (i.e. sodium chloride).
Is that sufficient? Móż commented,
Seriously, electrolyte drinks are just sugar, salt and flavour. Two of those things are very, very cheap.
Another comment was,
Any sports drink powder will do. Basically sugar and electrolytes.
Upvotes suggest people think this comment is important:
Make sure you get a real sports drinks, not lollie water sold as sport drink
Is salt sufficient as an electrolyte or is it important to have more (e.g. calcium, potassium, and/or I don't know what) during a ride?
What about other ingredients (proteins, amino acids, even fats, or whatever), do you suppose any of those are essential? Beneficial? Or should I take it that they serve to differentiate a store-bought product and maybe justify a high cost?
I get slightly inconsistent results from looking at the ingredients. Two of the products people recommended in comments were "Hammer" and "Rynopower".
Hammer for example has approximately (to within a factor of 2) equal quantities of each electrolyte:
Sodium (as Sodium Chloride) 80mg 4% Chloride (as Sodium Chloride) 120mg 4% Calcium (as Chelate) 100mg 10% Magnesium (as Chelate) 50mg 12% Potassium (as Chelate) 50mg 1% Manganese (as Chelate) 500mcg 25%
Calcium (as Calcium Carbonate, Calcium Chloride) 100mg 10% Magnesium (as Magnesium Oxide) 50mg 13% Manganese (as Manganese Gluconate) 3mg 150% Chloride (as Calcium Chloride) 60mg 2% Sodium (as Sodium Bicarbonate) 200mg 8% Potassium (as Potassium Bicarbonate) 100mg 3%
Whereas Rynopower has much more sodium:
Sodium 333 mg Potassium 85 mg Calcium 40 mg Magnesium 24 mg
The latter suggests to me, rightly or wrongly, that Potassium, Calcium, and Magnesium are trace elements which don't need to be replenished in a big way en route (as long as your regular diet include adequate calcium); whereas the former implies that you need as much extra of those other elements/salts as you do sodium.