This 'Home' Is a Literal Refrigerator for Your Sourdough Starter—and It Works Great

Devoted sourdough bakers eventually come to realize that controlling the temperature of their sourdough starter is one essential key to success. That’s because, unlike commercial yeast, which is single-use and ready-to-go on demand, a sourdough starter is a living organism (or, more accurately, a collection of living organisms, yeasts, and bacteria) that must be cared for regularly, not unlike a pet. And like pets, a sourdough starter gives back only what is given to it. Neglect it, and it will produce dull, flat, and sour loaves; treat it with love and attend to its needs, and bread will rise tall and true.

The needs of a sourdough starter are singular—to be given fresh flour and water on a regular basis and to be kept within its preferred temperature range. People sometimes casually refer to this practice as “feeding” a starter, but it is more accurate to call it a refreshment. That’s because, unlike feeding a cat or dog, you don’t give flour and water to the starter. Instead, you transfer a small portion of the culture to a fresh container of flour and water for it to both consume and inhabit.

How frequently a starter needs refreshing depends upon how often it gets used: In a bakery making sourdough bread day-in, day-out, it might happen two or three times a day. For a home baker making only one or two loaves a week, it happens every seven days or so; in between refreshments, the starter can be stored in the refrigerator, where the cold temperatures slow down its growth. This is a reliable and simple way to maintain a sourdough starter at home, but there is one major problem with it: Refrigerator temperatures (34-38˚F / 1-3˚C) are not really within its preferred temperature range. The bacteria and yeasts in a starter don't merely go dormant at refrigerator temperatures, they begin to die off; the longer a starter is held at those temperatures, the longer it takes to fully recover before its next use.

A sourdough culture's ideal temperature range is around 78˚F; when refreshed daily and kept at that temperature, a starter will usually remain in peak form at all times. Stored in the fridge in between uses, a starter usually needs one or more extra refreshments to restore the culture to full vigor. And even then it likely won't leaven a loaf of bread as well as one refreshed daily at room temperature. A home baker could keep their starter at room temperature too, but this would require a lot of extra work and much-wasted flour since the portion of the culture not used in each refreshment is typically discarded. 

The Sourdough Home: An Introduction

Brod & Taylor Sourdough Home

$119 at Amazon $120 at Williams Sonoma $120 at Sur La Table

Or instead they could keep it in a Brod & Taylor Sourdough Home, a $99 countertop "micro-fridge” designed specifically for storing and maintaining a sourdough. The Sourdough Home has precise temperature control from 41-122˚F (5-50˚C) and a chamber that can hold a container up to one liter in size (or several smaller ones), more than enough room for the average home baker’s needs. I’ve had a Sourdough Home for a few months now, and I have found it to work exactly as advertised: It cools (or warms) the starter to within 2˚F of the set point and holds it there indefinitely.

The Sourdough Home’s wide temperature range means it can be used in many different ways, depending upon a baker’s needs. The Home was designed in consultation with Maurizio Leo, the baker behind The Perfect Loaf, a website dedicated to all things sourdough baking, and the author of the 2023 James Beard-winning sourdough baking book, also called The Perfect Loaf. Since Leo inspired the Home, I reached out to ask him how he thought most home bakers would want to use one. 

“It depends on their baking frequency," he told me. “For example, since I bake super often, I have it set to 78˚F, and I just keep my starter in there.” Leo lives in Albuquerque, New Mexico, where average temperatures are above 78˚F for at least half of the year, so the Home serves as a tiny, temperature-controlled refuge for his starter. "It's kind of like a protective little area, and then it's ready to use whenever I want to start baking. For me, that's basically every day." The Home could work similarly for a baker somewhere or during those months when ambient temperatures are lower than 78˚F too (where I live in New England, our kitchen rarely gets above 68˚F from October to May).

Though Leo doesn’t run a bakery, he treats his starter as if he does, since he’s always working on recipes for his website. For more casual bakers, he recommends dialing things down instead. “Those who bake less often will want to set the Home to a lower temperature,” he said. “For most people, I’d recommend the three-day cycle that I've been working on, [with the Home] set at 50 to 52˚F.” A three-day cycle lets a home baker get away with refreshing their starter just two or three times a week while keeping it at temperatures far more hospitable to the bacteria and yeast than in a fridge so that it is ready to use with just a single room-temperature refreshment before adding it to a dough. This is pretty much how I’ve been using mine lately, and it has never been happier: My loaves are rising faster and expanding more fully than ever before, all with a couple of extra quick refreshments each week. 

There’s at least one other specialized use for the Sourdough Home: panettone, the highly enriched, sweet Italian bread traditionally served around the Christmas holidays. While panettone can be made using commercial yeast, the very best ones are made using a sourdough culture known as a ‘pasta madre’ or ‘lieveto madre.’ This culture is extremely fussy to work with, requiring even more precision and care than a regular sourdough starter; one of its many requirements is that it be fermented with a specific, narrow temperature range in order to avoid the buildup of unwelcome acidity.

Since I have zero experience with panettone, I reached out to my friend Olga Koutseridi, a baker whose gorgeous panettone I have been admiring for a long time on Instagram, to ask how she’d use the Sourdough Home to help make bread. “I would use it for the overnight maintenance of the lievito madre,” she told me. “I maintain mine at 16˚C, or 60˚F. It needs to stay at that temperature for 19 to 24 hours. It is non-negotiable: if you want to make panettone, you need a temperature-controlled environment that doesn't get hotter than 64˚F/18˚C, or the acidity will go off balance.” 

Koutseridi currently uses a mini wine fridge for this purpose, but she likes the wider temperature range, more compact footprint, and less-painful sticker price of the Sourdough Home: “For someone who's serious about making good panettone at home, the Sourdough Home makes total sense to me.”

Tips for Sourdough Home Success

Leo is currently working on a detailed Sourdough Home user guide for The Perfect Loaf website, but in the meantime, I have a few tips to share of my own:

• Be careful not to block the vents on the rear and sides of the device. The ventilation they provide is essential to keeping the temperature inside the home stable. (I learned this the hard way when mine quickly climbed nearly 30 degrees after having pushed it too close to the back wall of my kitchen counter.)
• You’ll also need to experiment with the ratio of your particular starter in order to determine how best to keep it in the Sourdough Home. I make mine using a 5:5:1 ratio, or 5 parts flour, 5 parts water, and 1 part starter, by weight, which works well with a 3- to 4-day refreshment cycle. 
• At 78˚F/26˚C, a healthy starter will typically triple in volume before it needs to be refreshed again. Gasses expand less when cold, which means you won’t see as much growth when you use a Sourdough Home at lower temperatures. My starter generally doubles in volume after three days at 50˚F/10˚C. (Like many sourdough enthusiasts, I use a rubber band to mark the initial level of the culture, and a tall, straight-sided container, so that it is easy to eyeball how much it has expanded.)

Like I said, the Sourdough Home works exactly as advertised: It cools or warms a culture over a wide range of temperatures, and holds it there stably for the long term. The Goldie by Sourhouse is another small proofer, however it only warms. For the casual or beginning sourdough baker, a home refrigerator is more than adequate to store a culture between uses, but for serious sourdough heads looking to increase the potency of their starter (or considering experimenting with panettone), the Sourdough Home might just be the start of something good.

FAQs

How often do you feed a sourdough starter?

From twice daily, if baking in a professional setting day in, day out, to once a week or so, for a home baker. In a Sourdough Home set at 50˚F/10˚C, you might feed it two or three times a week to keep it at optimal vigor.

What temperature is best for a sourdough starter?

The “ideal” temperature for a starter is around 78˚F/26˚C, at least if it is in active, regular use. For longer-term storage, cooler temperatures slightly above refrigerator temperatures are ideal, around 50˚F/10˚C. 

When should you put a sourdough starter in the fridge?

If you don't have the Sourdough Home and won't be able to feed your starter for an extended period—a few days or more—you should put it in a traditional refrigerator to slow the growth process. The benefit of the Sourdough Home is that you can set it to a specific temperature between 41-122˚F (5-50˚C), eliminating the need to move it from the counter to the fridge.

Why We're the Experts

• Andrew Janjigian is a bread and baking expert. He teaches bread-baking classes at King Arthur Flour and is working on a forthcoming bread cookbook.
• He's a frequent contributor to Serious Eats, having also tested bread ovens.