This is my first attempt at all grain brewing and was wondering if anyone knows approximately how long the fermentation process should last?
It depends on several factors.
1. How active was the starter or yeast packet?
2. What's your fermentation temperature?
3. Did you oxygenate the wort?
4. What yeast did you use, and what was your OG?
In my hands, using a freshly crashed starter of WLP-001, 007 or Bell's 2HA in a wort of about 1.058 SG and fermenting at 68F, mine will finish reliably in 12 - 14 days. On the other hand the GF's Kolsh (same conditions but OG 1.045 and WLP-029) is limping along at 24 BPM after only 3 days! Past experience says her brew will be done in 10 days.