How many grams of beans can you roast Questions › Category: About zenroast › How many grams of beans can you roast 0 Vote Up Vote Down zenroastteam Staff asked 7 years ago what the maximum grams of coffee I could roast was. how many grams of beans can you roast at one time? 1 Answers 0 Vote Up Vote Down zenroastteam Staff answered 7 years ago You can roast about 100g of beans at one time. But the more it’s heavy to shake and difficult to roast evenly. So I recommend about 80g – 90g.