Buzz
While 'lukewarm' generally refers to something that's neither hot nor cold, there are specific situations where a precise temperature is needed. For example, when you're baking bread, giving a baby a bath, or having breakfast with Goldilocks. So how warm is lukewarm exactly? The simple answer: it varies.
When Dutch physicist Daniel Fahrenheit and Swedish astronomer Andres Celsius developed their temperature scales in the 18th century, the term 'lukewarm' had already been used for centuries. According to the Oxford English Dictionary, it comes from the Middle English term 'lheuc' (also spelled 'leuk' or 'lewke'), which means 'tepid.' In a 14th-century poem titled 'Prick of Conscience,' an anonymous author wrote: 'Als a lewke bath nouther hate ne calde,' which translates to 'Also a lukewarm bath neither hot nor cold.'
In essence, 'lukewarm' wasn't initially a scientific term, and it still isn’t considered one. However, people often have a certain temperature range in mind when they use it. According to The Spruce Eats, some define lukewarm as the body temperature (98.6°F), while others equate it to room temperature (around 70°F, give or take a few degrees). But when it comes to baking bread or taking baths, lukewarm tends to be slightly warmer.
The Mayo Clinic and Nationwide Children’s Hospital both recommend that a baby’s bathwater should be around 100°F—warm, but not hot. This temperature range is also suitable for activating yeast when baking bread, though it varies depending on the type of yeast. According to Red Star Yeast, cake yeast (sometimes called 'wet,' 'fresh,' or 'compressed' yeast) requires water between 90°F and 95°F, while dry yeast needs water between 110°F and 115°F. Bob’s Red Mill explains that instant yeast requires even warmer water, typically between 120°F and 130°F. If the water is too hot—140°F or higher—the yeast won't grow.
As for Goldilocks, there’s still no definitive answer on what her ideal porridge temperature is—maybe she’ll opt for bagels instead.
