[sircastor]

Your note about the sweetener packets makes me curious if diet soda syrup lasts longer. This has been a reason for me to hold off on putting together my own carbonation setup as, in spite of how much soda I drink, I still don’t think I could move through the requisite 2.5 gallons of syrup before the expiration date hit. I wonder if the aspartame suffers the same hydrolysis in syrup.

[ChuckMcM]

It does! (less water, so less hydrolysis) "name brand" syrup however isn't particularly economical at retail however[1]. Not too surprisingly there has been a rash of restaurant bankruptcies during the pandemic and so buying "used" soda fountain gear is actually pretty easy (at least in the western US) these days. I actually have an Elkay "water machine" which does carbonation (as well as chilled and not chilled still water) although its carbonation chamber is too small to give a good fizz like the commercial units do. (more Perrier like, less fountain soda like). That said there are also relatively few powder mixes that take into account carbonated water. There was an AWESOME Grape Crush one (that was sugar free) but since it tasted poorly when mixed with still water it was discontinued (having a soda water tap is not the normal situation).

One of the more interesting ideas (and also impractical) are the "mini-syrups" that are used in the multi-beverage dispensers with the touch screen at places like Movie Theaters. Good luck getting hold of those. I briefly had a line on getting them from a local AMC because I knew the manager who wasn't averse to re-selling them to me at cost but she changed jobs when the pandemic made theaters non-viable. The existing Coke branded dispensers are so loaded up with various DRM/telemetry that even if you can get one at auction (which you normally can't since they are leased, not sold) it would be quite the reverse engineering process to get it to work "disconnected" from the Coke network.

[1] Funny story about how I spent four months trying to buy Diet Dr. Pepper syrup at the "restaurant" rate (which was about 1/4th the "retail" rate) elided.

[notjulianjaynes]

One issue with those machines is the sweetener is mixed with the flavor ingredients at the fountain. That's how they fit all those flavors in a refrigerator size package. Each flavor pack is about the size of a box of mike and ikes, but there's also a "bib"(2.5 gallon bag in box)[1] of non-nutritive sweetener that's shared by all the diet flavors. Corn syrup gets routed in from a big tank in the back along with water and c02.

In practice if you wanted some kind of home setup, you'd be much better off just buying the normal box of syrup like they use in fast-food restaurants, gas stations, etc.

[1]https://www.ebay.com/itm/184564418337

[ChuckMcM]

Wow, why am I not surprised :-). If the normal boxes had been reasonably priced when I was pursuing this I would have gone that route. At the time the best I could do was a bit under 0.02/oz based on the 24 oz bottles or 2 liter bottles depending on sales. The places that would sell me syrup had the result coming in at 4.2 - 6 cents/oz which would have increased my costs considerably.

[robk]

Hello old Google coworker I had the same setup in Fort Mason in 2004 and was able to get the SF wholesaler to sell to us pretty regularly. Iirc it became a lot easier lately to just find generics on eBay and worry less about getting the hookup. Diet red bull was the holy grail but we found an okay proxy on eBay too.

[ChuckMcM]

Nice! And yes, I did consider the ebay route for a while but I felt I didn't have a good handle on how bad "bad" syrup could be.

[andjd]

Note also that most soda fountain syrups also use saccharine instead of aspartame. This is probably so the syrup doesn't go bad as quickly. The transition to aspartame was driven by a study that showed that saccharine caused cancer in rats. That study had issues, but it had enough of an impact that consumers looked for alternatives. For soda machines, there usually isn't an ingredient list visible to the consumer, so that pressure to switch to aspartame didn't exist. There was a class-action lawsuit a few years ago claiming harm from the fountain formulation of diet sodas being different from the same brand sold at retail, but I believe it was thrown out.