If you do go with an airtight lid, you'll want to "burp" the container every now and then so the gas doesn't build up inside and cause it to explode. The perk of a glass jar is you can see what's really going on inside your starter, not just on the surface.
Getting ready to bake
Let it rest at room temperature for about 8 to 12 hours, until bubbly. Repeat as necessary, every 12 hours, until you notice the starter doubling or tripling in volume in 6 to 8 hours. That means it's strong enough to leaven bread.
Sourdough starters do not in fact breathe and therefore do not need to have access to fresh air. However, the organisms in your sourdough starter do emit carbon dioxide, which is a gas that can build up inside the jar.
Yes, you can bake with sourdough starter straight from the fridge.
Add 1 scant cup (113g) flour and 1/2 cup (113g) lukewarm water to the 1/2 cup (113g) starter in the bowl. Mix until smooth, return to its jar or crock, and cover. Repeat this process every 12 hours, feeding the starter twice a day.
Room-temperature starter should be fed every 12 hours (twice a day) using the standard maintenance feeding procedure: discard all but 113g, and feed that 113g starter with 113g each water and flour.
It's a naturally occurring alcohol called "hooch" that is produced by the fermentation process. It's also sign that your sourdough starter is hungry. Pour as much of the hooch as you can off the top, then stir your starter before feeding it.
If you do not plan to bake with the starter on the day it is fed, refrigerate 3-4 hours after feeding. Feed refrigerated starter weekly. If you go longer than a week without feeding, you may want to give the starter two feedings before using.
Generally a starter can stay at room temperature without feeding for a maximum of 3 days. After that you will need to give the starter few feedings before you can use it again. This is because it will become less strong and it will need time and food to become strong again.
Warm up: If you choose to keep your sourdough starter in the refrigerator, allow it to warm to room temperature for several hours before feeding. We generally take ours out of the fridge the night before we want to make sourdough, then feed it in the morning. Avoid adding cold water, which will also slow it down.
METAL: Stirring your starter with a metal spoon or placing it in a metal bowl won't kill your starter. While we don't recommend making or keeping your starter in contact with reactive metals like copper or aluminum, stainless steel is harmless.
You'll want to cover your sourdough starter, but only to stop things from falling into it and to keep it from forming a skin on top and drying out. Otherwise, remember that your starter is alive and needs to breathe a little bit. A lid is fine, so long as it's not completely air-tight.
As part of the feeding process, most bakers discard some of their sourdough starter before adding fresh flour and water to the jar. This is done to refresh the acidity levels (think sweet vs. sour smell) and to manage its overall growth in size. This technique is crucial for successful sourdough bread.
You most definitely can bulk ferment sourdough too long. If you leave the dough to ferment for too long, it will become "over fermented". Over fermented dough will lose its structure and become a soupy, sloppy mess that you will not be able to shape.
The discard is just the sourdough starter you're not currently feeding or baking with. It's called discard because it often gets "discarded" during feeding. If you don't "discard" some starter during feeding your starter will just grow and grow and grow until you're staring in a remake of The Blob.
You can store your starter at room temperature indefinitely if you make sure to feed it almost every day. A missed day here and there won't hurt an established starter, but if you starve it too long, it will die. Note: For the float test, drop a small amount of starter into a glass of room-temperature water.
Sourdough starter can be frozen, if you would like to store it for a long period without feeding. To do this, double the amount of flour added at feeding so that it is a very thick paste, place in an airtight container and freeze for up to 1 year.
Should I cover my sourdough starter? I like to keep mine covered loosely to keep anything from falling inside the jar and to keep the starter from drying out. The lid does not have to be airtight. I loosely place a glass lid on top, but it's not sealed shut.
Can I Use My Sourdough Starter Right After Feeding? It's not a good idea to use a sourdough starter right after feeding. Ideally you should wait at least 2-4 hours.
Overfeeding a sourdough starter will put the culture out of balance. When you don't feed your sourdough starter enough, it will become very acidic because you aren't giving it fresh flour or fresh water and the waste will build up inside the jar.
The rule of any kitchen is “When in doubt, throw it out,” but I wouldn't panic and toss your starter if you only missed 1-3 days of feeding. If it's more than 3 days AND you have a warm kitchen, you'll have to make the call based on how well you know your starter.
What if I miss feeding my sourdough starter? If you miss one of your starter feedings, it'll be just fine. Give it a feeding when you next remember it needs one, and continue with your daily feedings as usual.
The temperature of the water will affect the activity of a sourdough starter. The ideal temperature for a sourdough starter is between 24 - 28C (75 - 82F). Particularly if you are working in a cold climate, feeding your sourdough starter with warm water will help to boost the activity of the bacteria and yeast.
All-Purpose Flour: All-purpose flour, which is a blend of hard and soft wheat, is a popular choice for feeding sourdough starter. It provides a good balance of protein and starch, which promotes a healthy fermentation process. Bread Flour: Bread flour has a higher protein content compared to all-purpose flour.