I am back with this series of do’s and don’ts of sourdough starters to help you understand the science behind them so you can make more informed decisions in a time where everyone seems to have “the ultimate recipe and process” for sourdough. Spoiler alert: sourdough is not a one-fits-all kind of thing. This week’s topic is: feeding ratios.

Last time we talked about the age of our sourdough starter and why claims that a starter not working because it was too young were probably wrong, and the issues had more to do with how often the sourdough starter was being fed.

After learning how often we should feed our starter, the next question is “How much should I be feeding my starter?” So let’s dive into Feeding Ratios!

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What is a feeding ratio?

Feeding ratio refers to the proportions of sourdough starter, water, and flour we use to refresh our starters. Typically, everything is based on the amount of starter. I’m sure you’ve seen 1:1:1 ratios, or 1:2:2, or 1:10:10… It’s usually given as starter:water:flour, so a 1:1:1 ratio means 1 part starter, 1 part water, and 1 part flour. 1:2:2 means 1 part starter, 2 parts water, and 2 parts flour, and so on.

What happens if I change the feeding ratio?

Nothing, just that your starter will peak at different times. You can adjust feeding ratios to your needs and to whatever your starter needs. In the first post of this series, we talked about how a 1:1:1 ratio might be more convenient if you’ve been feeding your starter too often. But maybe your kitchen temperature and overall conditions allow you to keep a starter at room temperature and feed it at a 1:1:1 ratio once or twice a day. Or maybe you live in a very warm and humid area, where a 1:1:1 ratio is too limited and the starter peaks too fast. If that’s the case, you will probably benefit from a 1:10:10 ratio.

If you like to keep your starter in the fridge, maybe you prefer to refresh it a few times before baking and, in this case, you can use the standard 1:2:2 ratio. Maybe you prefer a “no discard approach” and just take a little bit of starter from your jar and feed it at a 1:10:10 or 1:15:15 ratio to end up with the exact amount of starter you will use on your recipe.

Ideal feeding ratios

The ideal feeding ratio is the ratio that works for your schedule and/or needs is the ideal ratio for you. And this ratio can change at any time. Sourdough is alive, but we have a certain control over how fast or slow we want it to grow.

For a given temperature

The smaller the ratio, the faster it’ll grow because the amount of food for the bacteria is more limited. A larger ratio will result in a starter that will take its sweet time to peak.

Example 1: You have a few slow hours in the middle of the day and it’s the only moment you can prepare your dough. Then feed your starter a 1:1:1 ratio early in the morning and it’ll be ready around the time you’re free.

Example 2: You are having an extremely busy week. You can only prepare your dough tomorrow sometime during the morning but you only have time for your starter today. Then maybe a 1:10:10 feed today in the afternoon will work.

For a given feeding ratio

The higher the temperature the faster your starter will peak. And the lower the temperature, the longer it’ll take to peak.

Example 1: It’s winter and your kitchen is usually at around 66-68F (19-20C), you can feed your starter a 1:2:2 ratio on Friday evening and it’ll be ready in the morning. You can start preparing your dough on Saturday morning.

Example 2: You live in a very hot and humid place. Maybe higher feeding ratios (plus using fridge cold water) is what works for you. Feed your starter in the evening at a 1:15:15 ratio and it’ll be ready the next morning, or feed your starter at a lower ratio in the morning, and you can probably start your dough early in the afternoon.

All these are examples, of course, you know your starter better than anyone and can probably anticipate how it’s going to behave. But what if you are new to sourdough? Then let’s experiment a bit!

How to get familiar with your sourdough starter

If you don’t know your starter very well, you need to record its behavior for a little while. For that follow these simple steps:

1. Kitchen temperature: Record your kitchen temperature, I usually just follow my house thermostat, but you can use any thermometer.
2. Feeding ratios: Based on your temperature choose a feeding ratio. Unless you live in extreme cold or heat conditions, I would go for a 1:2:2.
3. Time to peak: Record the time of the feeding and keep an eye on your starter until it peaks, then record that time and calculate how long it took.
   
   

Anything from 8-12h cycles using a 1:2:2 ratio falls under normal behavior for my starter. During winter it grows slower, during summer it grows faster. My house has AC, in winter we keep it from 66-69F (19-20C), and during summer we keep it 70-74F (21-23C), but when we are not home we let the temperature increase a bit, so during North Carolina’s hot summer days, I sometimes use 1:10:10 feeding ratios.

Can I adjust the water?

A typical liquid sourdough starter is a 100% hydration dough. But sometimes it’s interesting to play with the hydration levels of our starters. For example, if you’re working with Lievito Madre, you know it is a starter at 40% hydration (ish). Dryer starters tend to be a bit sweeter and less acidic and they’re fabulous for sweet breads. But they do take a bit of extra elbow grease to maintain. On the other hand, liquid starters at 100% hydration are very easy to maintain. But can you use 85% hydration? or 125%? of course! You’ll have to calculate how much water you need.

How do I calculate the water for feeding ratios?

If you want to experiment with other water contents in your starter, you need to know just a basic concept. If you want LESS water than flour, you will have to multiply the flour content by 0. something and if you want MORE water than flour you will have to multiply by 1.something

Example 1

If you want a starter at 75% hydration, then you decide the ratio of starter and flour, calculate the flour, and finally, multiply that amount by 0.75

Let’s start with a 1:3 ratio of starter:flour and 10 g of starter. This means we have 30 g of flour (3 times the amount of starter). To calculate the water we multiply the flour by 0.75:

30 x 0.75 = 22.5g of water

Example 2

If you want a starter at 125% hydration, then you decide the ratio of starter and flour, calculate the flour, and finally, multiply that amount by 1.25

Let’s start with a 1:5 ratio of starter:flour and 15g of starter. This means we have 75 g of flour (5 times 15g). To calculate the water we multiply the flour by 1.25:

75 x 1.25 = 93.75g of water

(you can round it up to 94 or 95 and it will be fine)

Can I use volume instead of weight for feeding ratios?

Working with weights allows you to be more precise and it makes the process easier to repeat. Weights are much more accurate to measure than volume. At least with regular home equipment. If you’re new to sourdough, bread baking, or baking in general, I would strongly suggest you use weight instead of volume. This way you’re already avoiding possible differences between feedings that could potentially lead to different outcomes. You will have a better picture without doubting if the differences you see come from off feeding ratios or something else. If you want an affordable scale I use THIS ONE, I’ve used it for many years and I think I’ve changed the battery once. Baking doesn’t need to be expensive!

With this being said, you do what works for you, if you are comfortable using volume measurements, use them. Just try to be as precise as possible (Can you tell I’m a scientist? 😉 )

How do feeding ratios work with other flours?

As far as bacteria go, the same! However, different flours make different doughs so you might not see your starter peak as a wheat starter would. You will have to find how the peak looks for different flours. Also, some flours absorb a lot more water than others, and a 100% hydration starter might look very different depending on the flour.

All this might seem a bit complicated but I assure you that once you start, you’ll understand right away and you will start to understand your starter much better!

One last thing about sourdough starters

You don’t have to put yourself in a box and follow exactly what others are doing. Use the feeding ratio that works for you, the hydration that works for you, and the measurements that work for you (volume vs weight). The idea of this series of posts is to give you enough information so you can make an informed decision that will work for your particular needs. Don’t be afraid of experimenting!

Here are a few recipes that you can try if you’re starting in the art of sourdough!

Sourdough burger buns (cookout time is here!)

Sourdough marble rye bread (one of the blog favorites!)

Sourdough Challah (another favorite!)

Happy Baking!