There are many methods and answers to this, but we offer a dedicated blog post, and a detailed FREE GUIDE on the topic.

You only need one starter, and you can use just about any flour you like for it. Some flours are better suited to specific breads, but a starter of mostly or all AP or bread flour is suitable for most breads. If you want to make a loaf that calls for a different starter, you can build a levain from a portion of it.

You don't need to keep much on hand. If your starter is healthy, you can turn 50g of active starter into more than 1kg (1000g) in two feedings over 24 hours!

There are very few things that you need to make sourdough. That said, if you want to make consistent bread, the best way to accomplish that is by weighing your ingredients. Volume flour measurements are wildly inconsistent and starter even more so. Water weight and volume are identical in metric, so 1ml water = 1g water.

Hydration is the amount of water in a dough, expressed as a percentage of flour. This is known as a 'baker's percentage'. You calculate it by dividing the water amount by the flour amount, then converting from decimal to percentage (ie moving two places to the right).

Baker's percentages are the basis for all dough formulas, and are used to easily scale recipes up or down, or to make adjustments to ingredients. The basis for them is that flour is always 100%, and everything else is expressed as a proportional percentage to that. They are tricky to understand at first, but the more you practice using them, the more intuitive it will become. There are plenty of calculators you can use, but this one is pretty good: http://brdclc.com/

Starter feed ratios are generally expressed in this format [1:1:1]. This means taking 1 part starter and feeding it 1 part flour and 1 part water (by weight). This is the most basic feed ratio, but you can increase the amount of food, and as long as you add the same amount of water as you do flour then the hydration of the starter will remain at 100%, which is equal parts flour and water. a feed ratio of 1:2:2 means taking 1 part starter and adding 2 parts flour and 2 parts water to it. You can increase this to any amount, such as 1:5:5, or 1:10:10 or more.

As a general rule, the greater the amount of flour/water to starter, the longer it will take to peak, and the longer it will remain at peak. This can be useful if you want starter to be ready in the morning for instance, but the exact ratio will take some experimentation and observation on your part. Ambient temperature will affect fermentation rate, as will other factors like starter strength. You can also use a lower feed ratio if you need more starter and want it ready sooner, eg 2:1:1, which is 2 parts starter to 1 part flour and 1 part water.

There is a wide range of temperatures that you can use, but for lean sourdough bread (not enriched with fat or sugar) the generally accepted desired dough temperature (DDT) is 73-78F. This range favours yeast fermentation and will catalyse good initial fermentation after mixing.

At the most basic level, fermentation is a product of time and temperature. In other words, the rate of fermentation will be faster at warmer temperatures, and slower at cooler temperatures. In the case of sourdough, you have to consider that the lactic acid bacteria also ferment in addition to the yeast. Lactic fermentation behaves differently, and at different ideal temperature, so your temperature will not only affect time of bulk fermentation, but also the type of fermentation.

You won't, at least not to begin with. You will learn it gradually the more you bake, as long as you pay attention to what you are doing, and try to limit the amount of variables from bake to bake. Try using a single recipe and the same utensils/containers, keeping the temperature as close to the same as possible and refine your technique and timings until you can confidently reproduce your results. Then branch out by changing one element only and see what effect that has on your finished result.

This could be a few things. You might not have developed enough gluten strength in your dough. Or you might have over proofed it, and the gluten is beginning to break down. It could also be some combination of those two, or something else like too much water in the dough for the flour you are using. Just keep at it, you'll get better!

Fermentation isn't the only thing, but it's everything! You are going to have a lot of questions that you think all have a different answer. Like why is my dough hard to score? Or why is my crust hard? Or why is the colour so light? Or why [insert question here]! The answer to many, many questions is fermentation. Get fermentation right and you'll be amazed how many other questions this answers.

Practice. Literally keep at it until it starts to make sense. It might take 100 loaves, but the more you do it, the better you'll be able to judge fermentation. Sourdough is simple, but not easy, and it will likely take you years to even come close to mastering a basic loaf of bread.