Hi Chris, thanks for saying hi to us all.
i'll try and pick through some of the points, questions or uncertainties that you have mentioned.
First off, as you can tell from my signature i rate Berry's book and as a newcomer to winemaking you'll find it full of good info and ideas/recipes. The only criticism worth taking seriously of the book is that he tends to make wine on the sweet side. However all the info for tailoring wine to your tastes is in there. As you have some brewing background already you'll find it a breeze. There are occasional misprints to watch out for, but perhaps your new edition has these corrected. For example one recipe mixes up the listed quantities when converting from 'per gallon' to a 2 gallon brew. Its correct in the descriptive part, but they forget to do the math in the table. Can't remember which recipe, only found one like that and brewed plenty from his book. The size and quality of some exotic fruits has also improved greatly over the decades and you may want to take this into consideration too, pineapples for example. Anyway, all very minor points, and no cause for concern, it is an introductory text so in time you may want something more specialised, personally i use the www plenty when embarking on new brews, often i revert to berry but maybe stick in a little something extra that i see while surfing.
Degassing wines ... TBH i haven't bothered with this until reading through the shiraz kit instructions that i have just made. It seems a bit of a faff, but i enjoy it, i imagine i look like i'm cradling a newborn while i do it, and i get nice winey whiffs through the airlock at the same time. I'll probably continue to do it now for other wines and will be curious to see how much it improves the wines apart from perhaps speeding up the clearing process. Flavour wise i imagine it should help too as there will be less oxidation but how much?. And you're right ... while fermenting you want dissolved oxygen in the brew for the yeast.
Topping up ... i usually just add water to my wines if the demi-john needs topping up. I have usually followed berry's recipes and found that water works ok. Perhaps because berry is on the sweet, and often strong, side so water is ok. It does mean that if you want to know your figures precisely (OG, FG and ABV) then you'll have to do some maths, which i can't be bothered with for the most part. I think berry recommends topping up with the same liquid that you started your brew with, which avoids the maths, but may have you demi-johns accompanied by lots of little satellite fermenting vessels.
Veg wines ... i felt much the same as you, but at the tail end of last year i got a parsnip wine on the go, and its gonna be a beauty. absolutely clear, tastes fruity, citrus, white grape wine, not a hint of parsnip. Really pleased with it but all accounts suggest about a year before drinking so i'll be patient yet! I'll be trying pea pod wine if we get enough from our garden.
as always i've rambled on a bit! I'm sure you'll get the benefit of other folks' experience too regarding some or all of what i/we have said. happy brewing :drunk:
as if i didn't write enough already .... an after thought. When i made the green tea and ginger wine i used muslin bags (sterilised and rinsed well ofc). It made it easy to remove the solids when i wanted (at two different times) and squeeze the juices out too. Might help with the loss of volume you mentioned. I took care to avoid the added risk of infection by rolling the bags daily so that the surfaces didn't dry out or go vinegary or whatever.