I think I messed up my root beer

I'll start at the beginning. I heated up 1.5 gallons of water just hot enough to dissolve 4 pounds of sugar. I let that cool down while I sanitized my equipment. Then I mixed the sugar water with 3.5 gallons of water from the refrigerator. It wasn't cold but definitely wasn't hot. Kind of semi-warm, I guess. I pitched the yeast on the mixture and stirred it in. I bottled in 2-litre bottles. Now I'm starting to worry if the mixture was too hot for the yeast and if I pitched incorrectly, if that's possible. Sorry for the noob post. I've never made soda before.

Sounds like you did just fine. Wait a few days to see if the bottles get hard. I killed the yeast on my first batch of root beer, but I know my water was WAY too hot. Do yourself a favor and get an instant read thermometer for your next batch. Aim for about 75 degrees before adding yeast.

Thanks for the reply. I checked the bottles this morning and they were hard with visible bubbles on the sides so I put them in the fridge. I'll pour a glass in a few hours. I'll definitely take that advice about the thermometer. Thanks again!

You're welcome! I found my root beer tasted best after about 3 days in the fridge. The flavor kind of mellowed a bit. If you don't like it after one day, let it sit for a couple more days then taste it. Enjoy!