JY303 is our 100% natural, non-GMO thiol producing yeast. Genetically modified thiol producing yeasts can be very active in their thiol releasing activity, especially if genes from bacteria are expressed. That (artificial) activity can release large amounts of sulfur compounds, potentially resulting in a burning, unpleasant and artificial aroma. Our strain is not genetically modified and is naturally equipped with thiol releasing activity, resulting in much less sulfur and a more pleasant thiol aroma. The strain produces citrus, pomelo and pineapple aromas and flavors, depending on the ingredients used by the brewer. Its not the best attenuating strain, do not let the jackets come on at the end of fermentation and let it rise to mid 80ies (~30°C). If you want to go over ~18°P you have to make your wort very fermentable.