apologies for introducing myself here instead of in the dedicated subsection.

I am new to bread making having initiated one month ago only. Italian currently in Hong Kong.

To add flavour to my bread making machine made bread, yesterday baked my first loaf with a small biga of 50 grams only.

For the biga followed proportions defined by Piergiorgio Gorilli [1]. A Knight and Master baker of exceptional skills I have never heard of before approaching the subject. One never stops learning.

Have few doubts. I am about to share one here with the hope collective wisdom will help to speed up the learning process.

Covering the biga container is required to prevent excessive moisture evaporation. Cellophane film, cellophane with holes and a simple cloth were all mentioned by different sources. Plastic container with air tight plastic lid also. Cellophane with holes is what I employed for the first fermentation step in the fridge. "Long" biga process. At the end appeared darker and dryer than expected. For room temperature fermentation switched to cloth at first but soon replaced it with cellophane film without holes. Dryness was apparent already. So which lid is the right one for letting biga ferment properly?

Side note: some mentioned here freezing the biga for subsequent uses. It clearly kills all bacteria. Is not deleterious to flavour and in general the leavening process?