I saw you like coffee, but it worsens your stutter. You arent alone. Caffeine has an acute cortisol and adrenaline increasing affect that disappears with chronic use. It also has an acute lactate increasing effect. Long term caffeine use, especially coffee with added sugar (as caffeine lowers blood sugar) will bolster your stress response and wont have the acute cortisol/adrenaline surge. If you notice your nose getting slightly clogged with your coffee (or at any time, really), you have high lactate. A few hundred mg of B1 will lower your lactate and improve your speech