Why does my homemade kombucha always have a weird, vinegary smell even when I follow a simple SCOBY recipe and use filtered water?

I totally feel you, I've been there too when I first started brewing my own kombucha at home. The vinegary smell can be really off-putting, but don't worry, it's pretty common, especially when you're just starting out. From what you've described, it sounds like you're doing everything right, but I think the issue might be with the fermentation time or temperature.

I've found that if the fermentation time is too long, the kombucha can start to taste and smell more vinegary. This is because the bacteria and yeast in the SCOBY are feeding on the sugars and producing more acid, which gives it that strong smell. So, you might want to try shortening the fermentation time and see if that makes a difference. Also, make sure your brew is at a comfortable room temperature, between 68-72°F, as this can affect the fermentation process.

Another thing to consider is the health of your SCOBY. If it's not healthy, it can affect the flavor and smell of your kombucha. You can try looking for any signs of mold or contamination on the SCOBY, and make sure you're handling it gently and keeping it clean. I've also heard that using a larger SCOBY or adding a bit more starter tea can help balance out the flavor and reduce the vinegary smell.

I hope these suggestions help, and you're able to get your homemade kombucha tasting and smelling just right. If you have any more questions or need further troubleshooting, feel free to ask, and I'll do my best to help you out. Good luck with your brewing, and I hope you'll be enjoying delicious homemade kombucha soon!