Because of different altitude I have found its best to own a candy thermometer because best temp is 240 degrees Fahrenheit to set jam. Where I live a rolling boil is about 250 which is to hot so get temp to 230 after adding pectin and hold 230 for 1 minute for perfect soft set every time. If you prefer a stiffer set which I do for some of my friends then get it up to 240 degrees Fahrenheit before adding pectin then take it to 240 degrees Fahrenheit again and hold for 1 minute