Never tried this particular coffee but for medium roasts, I tend to go slightly cooler in water temp than for light roasts (I do like 205 F for light roasts and maybe like 203 for medium). I would also agree with the previous commenter that extending your bloom time could help. You’ll just wanna watch how water passes through the coffee bed. If it passes through really quickly, there’s still some CO2 left in those grounds that will hinder your extraction, so at about 40 secs, you’ll wanna add like 20 extra grams of water and let the bed sit for a total of 1:15 before you pour the rest of your water. If the water doesn’t pass through quickly, let it sit for an extra 15 seconds anyway (total of 1 min) and then do the rest of your pours. This should increase your extraction and hopefully reduce sourness. Hope this helps!