If it's not quite ready when the oven is, you can always let it warm up on the counter for a while before baking it. So with a quick Google search I found this... http://tartine-bread.blogspot.co.uk/2014/01/guest-baker-chad-robertson.html. Yes.

If you’ve got any pent-up frustration or anger, slap and fold is a great stress reliever.

Not sure if that necessarily means you can't go for longer. So here are the the loafs I made yesterday using the Tartine method: They're not really good looking but the taste is great! An overmixed dough becomes slack, lacks elasticity, and can’t hold its shape at all. 1. Rubaud mixing works best for higher-hydration doughs—at least 75 percent hydration, according to Wilson.

Sourdough loaf using Tartine method. I would probably put it in the fridge about half an hour before baking the first loaf. Enter your email address to follow this blog and receive notifications of new posts by email. [...] In levain bread production, the autolyse technique can be a great benefit: "The levain contributes a considerable amount of acidity, one effect of which is the reduction of extensibility.
Many recipes build far too much and use just a fraction. Popularized by Chad Robertson of Tartine fame, the stretch and fold is the most well-known folding technique.

Under-proofed?

Ok I'll try like that, but I find it strange that it needs only that little time since in my apartment it's usually around 28-30°C, I mean it's not that hot.

Looking at the pictures of your dough in the banneton I'd say it had way more than doubled and likely collapsed from exhaustion either when you turned it out of the banneton or when it hit the oven. The most straightforward (and possibly most popular) technique relies on good old elbow grease. A dough can go from initial mixing to full gluten development in under 10 minutes.

Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. Move your hands slowly pulling the dough gently downwards to create some tension over the top surface of the dough, whilst you are shaping it into a round ball. Cloaking is often used for shaping round boules (but can be applied to other shapes as well) and is especially common when pre-shaping. Even armed with all this conceptual and technical knowledge—and combining it with proper fermentation—what is an aspiring (or experienced) baker to do? The time and temperature of both the bulk ferment and the final proof tend to be very variable for Tartine breads, if you do a search on this site.

I used to bulk 10 to 12 loaves worth of bread in large industrial "bus" tubs, performing coil folds every hour or two as I passed by in between the day’s tasks. Third, without repetition or experience, it is difficult to apply even tension to the folds, which can result in uneven distribution of both tension and gases. 3. The norm for what I imagine is 20% starter in a Tartine recipe I imagine 8-12 hours is about right. Some HTML is OK: link, strong, em. Folding dough is much the same.

This article is amazing and I'm just stunned that they've written that you should autolyse with levain (the article says that you'll get good results with or without the levain but the results surely can't be the same and it should have been explained better in the book!
If one is doing an all night autolyse then it's without the levain.