Dear R. Lebowitz, Regarding your shiur "Barbecue on Yom Tov", you mentioned a possible heter for turning off a gas stove on Yom Tov (possibly attributed to R. Moshe Feinstein, though unpublished), and speculated on the basis for the heter. What I didn't hear you mention was the concept of the pilot light. Until the 1990s or so, most gas stoves used a pilot light. This was a small flame inside or under the stove, that stayed lit all the time. When you turn on the gas to one of the burners, that opens up a valve to take gas through a pipe past the pilot light, and the ignited gas goes to the burner. When you turn off the stove, that connection between the pilot light and the burner is cut off, but the pilot stays lit. So when you turn off a stove with a pilot light, effectively you are just reducing the flame, not extinguishing it. Because pilot lights waste a lot of gas, and in some cases can cause a danger if the pilot light goes out, there was a change in how stoves are made, so modern stoves use an electric spark to ignite the gas each time you turn on the stove. So unless you have an old stove that uses a pilot light, the metzius is different from how it was in Reb Moshe's day, and his heter may not apply at all. I have a friend whose old pilot-light stove broke. She had a psak from her rav that she could turn off the stove on Yom Tov for exactly the reasons outlined above, but that she couldn't turn off a stove that didn't have a pilot light. So she found a used appliance dealer who had an older model of stove (no longer made) that still used a pilot light, so she bought that stove davka so she could more easily cook on Yom Tov. Regards, Jonathan Traum

Many people have been asking about the effect of the old pilot lights on this shiur. From Rav Moshe's perspective, the pilot light doesn't make a difference. His son Rav Dovid שליט"א has paskened that one may turn off a barbecue on יום טוב (even though there is obviously no pilot light) based on the idea that closing a gas valve is only גרם כיבוי. From a דאורייתא perspective, there is no difference between lowering and extinguishing a flame entirely, as both actions would constitute a מלאכה of מכבה. The only reason that we traditionally have assumed that lowering a flame is permissible while extinguishing a flame is forbidden on יום טוב, is that lowering a flame, though it is a מלאכה of מכבה, helps in אוכל נפש and is therefore permissible. Closing a flame never helps to cook the food, as one can achieve the same result by simply removing the food from the flame and leaving the flame on. Rav Moshe זצ"ל understood that if one were to lower a flame or extinguish a flame he is in violation of a מלאכה. There is no difference between the two so long as neither helps in the cooking process. Unless one holds of Rav Moshe's unpublished חידוש that lowering and shutting a gas stove top is only גרם כיבוי, it is forbidden to shut off even a stove with a pilot light because removing the pot from the fire achieves the same result. It should be noted that turning a flame on and turning a flame higher are both a מלאכה דאורייתא of מבעיר. From the perspective of מלאכת הבערה it would be equally permissible to make a new flame and to raise a flame if each action is used for cooking. The only reason that we do not light a new flame on יום טוב is that it is an איסור דרבנן of being מוליד something brand new.