hey crE
glad to see you are still checking this thread.
i deduce from all my online searches, that freezing your parsnips shouldn't adversly affect your brew. Glad to see you are still going ahead.
Details:
I cut out any part of the parsnips that was discoloured or slimey. i cut my parsnips into slices that were about 1 inch thick maximum, didn't peel but scrubbed well. they were boiled for about 20 minutes (got water boiling before adding parsnips then simmered) and i noticed that the middle of each slice had split after around 15-20 mins. They stayed whole and didn't break up (i wanted to avoid overcooking - pectin haze - , but also wanted to extract as much sugar and flavour as possible). Because of my procedure the sieve was pretty much redundant but still used as a safe-guard. i started fermenting with a crystal clear liquor that had an OG around 1100 (difficult to pin it down exactly 'cos i broke my hydrometer, but i measured it at around 1096 at 35'c ish after adding sugar (3.6 kg in 3 gallons - i hope you saw the edit on the basic recipe). some gravity was added from boiling the parsnips. can't say how much of it was sugars and if they were available to yeast, it was only a few points anyway. i used sauterns yeast (had a choice of a few varieties but took advice that narrowed it down to a variety that i had been advised - from experience - was good for country wines, and guessed white rather than red would be good). Let the pectic enzyme do its work for a bit less than 24 hours before chucking in the yeast. Added a little tartaric acid as i read it boosts polish and aroma/flavour. Used campden powder at the same time (ish) as the enzyme to get rid of potential nasties and also de-chlorinate the small amount of added water that had not been boiled. if all goes well then i may have a tastey wine with an ABV around 14%. but we'll only know in a year. i hope you are still around then to compare notes and results.
because of the pectin this is possibly my most adventurous brew. i usually steer clear of high pectin loaded ingredients. And this is one reason for the detail i have gone into. If this works out for you crE then i reckon it's a great confidence booster and you'll be up for trying anything and everything. if not, don't be discouraged, you will have had great cider, beer and wine results from the brews you have got going in the meantime. if it does work out then raise your glass with me and salute a sky is the limit attitude.
if you still have questions then ask away. there's no such thing as a stupid question, only a stupid answer, and we are both embarking on an journey into the unknown. I'm not an expert but my successful brewing experiences have lead me to branching out and trying this recipe.
happy brewing