Howdy,
while still sober on Chrissy day a few observations of late.
From previous posts you may be aware I'm a bit of a nutter for yeast nutrition, types, testing, conditions, reading. Don't get me wrong here I occasionally use Lowans especially when there's no quality issue to be gained like quick TPW neutral wash. If your not the type of brewer who likes to inquire and try things this is not a read for you.
Bought a proper new pH meter a few months back as old one was getting to need calibration every few days...didn't know they drift out of calibration with repeated use they sure as hell do.
These comments are based on approx. 12 brews over recent weeks and while I stand by them, results will vary by area due to issues like starting water pH so without testing your own location its just a guide to what's happening.
settled on using bicarb as it's available near every where , cheap and works. Other carbonates like chalk are very effective but dam hard to find as a food grade. Appreciate the variation between initial vs. perm alkalinity however.
Sugar/Grain UJSM variants and few Bundaberg food grade molasses washes and 4 x TPW's
Initial start temp: 29c-32 ...don't for get to re calc pH for temp correction.
Water: 7.1 ( Adelaide summer tap water, rested for 2 hours before use)
Initial starts: approx. UJSM's 6.8pH, molasses 6.5pH, TPW's approx. 5.5pH
2 hours fermenting ( after yeast stir in and growth stages) all seem to drop a full 1- 1.5 pts
Next day dropped by a good 2.5 - 4 pts.
The UJSM variants have a notable drop with typical 6.8 start with a running pH of as low as 3.7pH. The slow start molasses washes really do fire up with the addition of bi carb...it seems partly a solution to the typical lag these washes seem to have.
By gradually raising the pH over a couple of hours, avoiding yeast shock, with dissolved bi carb stirred in (1 heaped teaspoon in a warm pint of water x 3 doses) you'll recover .5 - .8pts no biggy,but does get them all around to mid to high 4's. Well and truly in the sour mash range, under any ammonia development that's commonly discussed on the greater than 5.5pH level. No bacterial infections in any. Btw did try to induce an ammonia wash once at about 6.2 pH...never happened.
Now here's the funky things
yeast activity makes a notable jump after adding bi carb and is sustained for a good day.
We're getting far better sugar use with hydrometers showing very low .90's or even flat .88's a drop of around .4 -6 pts on hydro at least. great result imho
ferment time is almost a 1/2 faster than expected.
The real bonus is the yield we're getting at least 20% - 25% better yield than unmeasured previous results. This may sound a little subjective and it is at this stage cos I've not recorded enough imho to be definitive, but I can say this is a notable result change and very happy with it.
This is a consistent result wether using the CM type still, old hybrid pot and unsure as yet too early on the 6 x perf plater. This view is also the same as previous posts made on starting pH and folk going way too low on pH scale especially for TPW's when citric is also added. These washes start low enough.
There's clearly a couple of schools of thinking on pH as a factor. Some see no value in measuring or adjusting and that's fine, no probs as they get a result they're happy with.
For me having invested the effort and time to build a new 6 perf plater in search of better spirit quality it's logical to invest some time and effort for the inputs to a wash as well. While a good still is a nice to have ...it's just one of several issues we need to come to grips with imho.
For inspiration and a further read if interested try John Palmers How to Brew site or Beersmith site
So ends my Xmas contribution for your post lunch snooze.
bt1