Baking sourdough bread is inherently old-fashioned, relying on natural fermentation and wild yeast instead of the simple, predictable commercial stuff. So it might sound anathema to bring a gadget into the mix. The trick to the Sourdough Sidekick — backed and branded by King Arthur flour — is that it promises to automate the boring bit of sourdough baking: starter management. It feeds your starter flour and water on a set schedule, ready for exactly when you want to bake, leaving you to focus on kneading, shaping, and the actual baking.
Like any single-purpose kitchen gadget, you’ll have to be confident you’ll get enough use to justify both the cost and the counter space. That’s doubly true here thanks to a few design quirks that make the Sourdough Sidekick frustrating to use if you don’t bake multiple times a week.
What Is the Sourdough Sidekick?
The Sourdough Sidekick is a joint project by FirstBuild — the GE Appliances innovation hub responsible for the viral Opal ice maker — and King Arthur Baking Company, which is why you’ll see the latter’s logo on the front. It launched with a crowdfunding campaign in March 2025, but it’s now available to buy directly from King Arthur for $179.99 — though it’s US-only. The device consists of a glass crock that holds the starter, a flour hopper on top, a detachable water tank in the back, and a mixing paddle that stirs the starter periodically. A simple interface with a few buttons and a dial controls the operation.
How It Works
The basic operation is simple. You drop a small amount of existing starter into the crock — 15 grams, or a tablespoon’s worth — and fill the two dispensers with flour and water. On Auto mode, you then tell the Sidekick when you want to make bread, and how much starter you’ll need for your recipe. It will drip-feed flour and water on a dynamic schedule that takes into account the local temperature, mixing as it goes, so that you end up with the right amount of starter, at its peak of activity, right when you need it. When the reviewer tested it with a simple white bread flour, this worked a treat. Setting the goal a few days out, leaving the device alone, and returning to find the starter strong, healthy, and ready to bake a decent white loaf. The bread came out slightly overproofed, suggesting the Sidekick produced a more active starter than manual feeding usually achieves.
You don’t have to use white flour, though any time you switch flours, you’ll have to spend a few minutes recalibrating the Sidekick to account for different densities. It handled most whole wheat and rye flours just fine, but when the reviewer tried an especially coarse-milled rye flour from a British miller for a dense Danish-style rye loaf, the resulting starter proved too thick for the Sidekick to mix properly, leaving dry clumps and thin patches. The starter needed more water to reach the right texture, but for that the pointedly simple Auto mode needed to be abandoned.
Auto Mode Limitations
Auto mode has several limitations. It is designed to work with exactly 15 grams of starter to begin with, so you have to weigh that out every time to get the proportions right. More annoyingly, it has odd limits to the minimum amount of starter it is willing to make. Set a bake day a few days out and it will let you produce as little as 150 grams, but aim for four days or longer and it insists on making at least 400 grams. That is far more than is usually used in a single loaf, resulting in much more discard — excess starter that won’t be used for baking — than manual feeding ever creates. There is no option to set the Sidekick into an Auto maintenance mode. You have to set a bake day, and that has to be within the next week. That is great if you know you will be baking soon and when. But sometimes you just want to keep the starter alive and don’t know for sure when you will next need a loaf. In that case, you either have to set an arbitrary target date and let it create some discard, or pull the main crock out of the machine, pop the lid on, and stick the whole thing in the fridge for a few days.
Ratio and Custom Modes
The Sidekick has two other modes that offer more flexibility. While Auto feeds your starter with flour and water at a 1:1:1 ratio, Ratio mode gives you a few preset ratios and lets you set the starter seed amount and feeding frequency. However, the odd limitation is that the set ratios only vary the proportion of starter relative to the other ingredients. Ratio mode does not let you add unequal amounts of flour and water to make a starter that is either thicker or thinner than normal — exactly what was needed for the coarse rye flour. For that you need Custom mode. This mode lets you set the seed amount, feeding frequency, and the exact quantities of flour and water you want at each feed. It allowed the reviewer to make a slightly looser starter for the rye, thin enough for the Sidekick to mix happily. It can also be used to create a custom maintenance mode with micro-feeds, or to start a new starter from scratch — the reviewer managed to get a healthy new starter up and running in four days — or to rehab one that is on its last legs. Just note that neither Ratio nor Custom mode take into account the ambient temperature, unlike Auto, so they will not adjust the feeding schedule if it is especially warm or cool, and you have to monitor starter activity yourself.
Smart Features and App
The Sidekick is not really a smart home gadget. There is a Wi-Fi option and an app, but they are easy to ignore. The app will send notifications when your starter is ready to use or discard needs to be removed, but the built-in screen does that too. Otherwise the app lets you check the Sidekick’s current settings, but not change them. There is little compelling reason to use it.
Cleaning and Noise
FirstBuild recommends that you clean the glass crock, lid, and paddle between every feeding cycle to prevent unwelcome buildup. It makes sense, but the crock and lid are not dishwasher-safe, so you have to wash those by hand. Less frequently, you are recommended to wash the water tank and flour hopper, but those at least can be popped into the dishwasher. The Sidekick is also oddly noisy. By default, it stirs the starter once every two hours, which involves 30 seconds of loud whirring each time. Since it will likely be in your kitchen, that is probably fine, but in a small space like a studio apartment, it might get on your nerves.
Who Is It For?
The reviewer noted that they could not see themselves buying the Sourdough Sidekick, but that was mostly because their kitchen is too small to justify single-purpose appliances (coffee machine excepted), and their fiancée was counting down the days until they could reclaim the counter space and get rid of the mixing sounds every two hours. They also did not bake enough to get the most out of it — one loaf a week at most and usually less. That meant taking the starter in and out of the Sidekick regularly, probably manually feeding it between weeks in the fridge, losing half the benefit of having it in the first place. But if they had a bigger kitchen and baked twice a week, they suspect they would be happy to own a device that takes care of the one bit of baking they do not really care for. The partner would just have to make peace with the noise.
Source: The Verge News