After reading Graham Wheeler's Brew your own British ale, in which he says:" a well brewed beer, kept its proper time, should not need priming or fining. A good yeast will clear down unaided, and residual dextrins in the beer will slowly ferment and produce perfect condition......" I have tried this on a a couple of bottles of dry Irish stout which did come into condition after 10 weeks at lowish temps (5-14 degrees centigrade), though the carbonation/head was pretty weak compared with the (normally) primed others. I have tried the same with my ESB which has been bottled now for 8 weeks at the balmy English summer temps of 12-16 degrees centigrade. Bottles have started to condition now but head still weak..... Taste brilliant. (but more so than the bottles that were primed normally? I can't compare them cos I quaffed the whole primed lot and thus have nothing to compare the un-primed bottles with). Just wondered if anybody else had experience of not priming?
The bottom line is that while this is by some considered the purest form of brewing, and good beer is attainable without adding finings or priming sugar, is it worth the additional effort and uncertainty?
There is certainly truth in not needing to prime some kinds of ales. Cask conditioned ale is often not primed, but simply transferred to the cask before primary fermentation is fully complete. There are also styles of beer, such as Stout and ESB that can have a very low carbonation level (1.5 vols CO2).
For beers that aren't low carbonation styles, I'm a little skeptical about the comment that the residual dextrins can provide sufficient sugar, since Ale yeast does not break down these dextrins in any significant quantity.
To my mind, adding a bit of priming sugar does no harm, has no affect on taste and helps consistently reach the desired level of carbonation.
I haven't used priming sugar for a few years now (having also read this book), but I always cask my beers rather than bottle. I transfer from the primary fermenter after one week, and I always end up with sufficient carbonation. This is probably because the yeast that is still in suspension and clearing down within the cask, is enough to produce the carbonation, and there will be enough residual sugars left over from primary fermentation.
The level of carbonation is bound to vary, even if you do prime. For example, some beers will have more residual sugars present after primary fermentation, and the yeast attenuation varies with the strain used. The type priming sugar will also have an effect.
You also mentioned the head of your beer. It is possible to have good carbonation, but hardly any head formation/retention in your beer (I've experienced this in varying degrees). I believe it may have something to do with the proteins in the beer that allow the formation of the bubble structure, and can be affected by the types of grist in your recipe, as well as the mashing/sparging method.