I'll add a little bit of information for your project. The byproducts of yeast eating sugar is 1) ethyl alcohol, or ethanol which is why you're making wine and, 2) carbon dioxide which is why the ballon inflates and popped. The fact that a new ballon inflated, albeit about half of the other as you site, tells us that carbon dioxide is still being released. As an FYI, CO2 actually protects the young wine from oxygen. So, like others, I'm t?
confident that your wine isn't ruined as a result of the ballon popping and going unnoticed for five hours.
Sounds like you were able to order a stopper and a air lock. As
@hounddawg recommended, "S" air locks are better than the two piece air locks IMHO.
A couple more things to remember:
1. Time is the best ingredient. Don't get in a hurry to bottle and drink. Certainly taste but don't bottle until the wine is completely see through clear and is no longer expelling CO2. And, let it age for several months before drinking. Likely not what you want to hear.
2. Consider really taking a run at this amazing hobby. Check out a wine
making kit at MidWestSupplies or another retailer and get a wine
juice kit. Wine juice kits have everything you need to make wine and you just need the proper equipment (wine making kit).
3. You'll find that the people on this forum are more than willing to provide help and guidance. All you have to do is ask as evidenced by this string.
4. And, remember, you're a Vintner (winemaker) now!