It sounds like that in order to eliminate problems with heartburn is not to drink a lot of coffee, I hate to sound obvious. Strong coffee isn't necessary to drink as much, all I have is a 1/3 of a cup of coffee a day at breakfast, and on rare occasions, I may have another 1/3rd at lunch, but I'm 67, the older most people get, the more likely to experience heartburn, or acid reflux from certain drinks and foods.
I do ride a bicycle, when I'm going on long rides of over 50 miles I put strong coffee into a small flask that holds about 4 ounces, and sip it while riding. Even when I go bicycle camping or touring I drink the same 1/3 cup of coffee I make when I eat breakfast, and put some into that flask to sip along the route.
The camping coffee is made differently than when I'm at home, at home I make it a number of different ways, but camping I only make pour-over coffee because the GSI Outdoors Ultralight Java Drip Coffee Maker I use takes up virtually no space and weighs next to nothing, it's the most compact coffee maker made.