Acidifying BIAB mash....??

[Kyle Richards]

Hey brewers

Just wondering what peoples procedure is with acidifying BIAB mash. It is my understanding it is more important to control pH with BIAB mashs because of the higher water to grain ratio. 

Do you'll use lactic or phosphoric acid or acid malt once grain is added or not or just rely on grain acidification 

 Also thoughts on 5.2 stabiliser?

Last couple brews have come out super astringent/undrinkable because I dropped 5.2 stabiliser and started adding citric acid and more gypsum to achieve mash pH of 5.2- 5.6. 

Cheers!

[Sam DT]

Yep a thinner mash will give a higher pH. How high depends on your water, where are you based? If you can find a water report plugging into a calculator like ez-water will help you figure out your additions. There's a couple of threads on water additions on the forum if you have a look.
I'm based in Christchurch and use 200 grams acid malt every batch plus 4-6 grams of gypsum, Epsom and cacl. From what I've read many people warn against 5.2 although having never used it I can't really comment.

[Kyle Richards]

Cheers Sam, I am based in Taupo, super soft water (Ca:6.8, Mg:2.8. Na:15, Cl:9.8, Sulphate:8, Alkalinity 39, pH around 7.2). The weird thing is, once I started using water chemistry spreadsheets, adjusting water profiles and pH I have ended up with crappy beer! 

I think I will start using acid malt and dial back my salt additions. Kind of dont trust my cheapo pH meter either!

What is the starting pH of your water in Chch? 200g of acid malt reduced pH by how much generally?  

[Sam DT]

Here's a link to a previous discussion - you can download one of my sheets which I uploaded.

I would note that I've changed my standard additions to 6gm each of Gypsum and Epsom and 4g of CaCl in order to push the hops forward a little more.

I mainly brew hop dominant beers as well which this kind of salt addition favours - you'd probably want to dial back the Sulphates and perhaps lift the pH slightly if you're into more malty beers.

Have a play with the sheet - I think from memory 1% acid malt drops your pH by about .1 on the pH scale.

[Matt Smith]

Is it possible that since switching to acid your PH is dropping too low? A total alkalinity of 39 isn't a whole lot to overcome. I would suspect with those numbers that your malt alone + a little Gypsum or Calcium Chloride would drop that PH pretty close to ballpark. Just a thought, perhaps that astringency your experiencing is actually tartness from being a little too acidic. If I was you I'd calibrate your PH meter, do a mash sans acid with a little gypsum, take a sample half way through the mash, chill it down to room temp then see if you are in the range, if not dose with acid and try again after another 10 mins.