Just got a new PH meter today, has temp and salts and others readings so will come in very handy, been having trouble getting consistant brews and thought had better start at the beginning with my water, All my water is rainwater, have no choice, no town supply out here, out of the tap @23 C was 6.8 and out of the filter which I use sometimes for brews came 7.34. way to alkaline. no wonder I'm getting crud malt flavor and equally bad hop flavors, what is a safe buffer to get this down to 5.0 5.2 . I have a tub of mash5.2 but no matter how much i put into a test jar couldn't get below 5.6,i am sure controlling PH alone will greatly improve product.
Anyone alter/adjust mash PH?
Wow...complex topic.
It is very difficult to give a simple answer as there are many factors involved. You really need to be looking at the pH of your mash, not your water. This is because many of the buffering chemicals that affect final mash pH are actually contained in the malt. Even type of malt used will affect the mash pH, with darker malt tending to lower the mash pH for a given water profile.
More important than the measured pH of your water for a given grist is the mineral content (in particular metal ions such as Calcium and Magnesium vs alkaline ions such as Carbonates and Bi-Carbonates). These ions interact with the buffering ions already in the mash to set the final mash pH.
About the only place where your water pH is important (for pH in normal ranges) is during the sparge, and this is because as the mash concentration reduces, the amount of buffering chemicals already in the mash reduces, allowing the mash pH to approach your water pH. If the pH rises too high, then you are at risk of rinsing harsh tasting tannins out of the grain husks.
I assume by "mash5.2" you are referring to the Five Star Chemicals 5.2 product? This is designed to work with the range of buffering agents and mineral ions already in a typical mash due to the grains. You probably won't see the full effect with straight water.
In terms of hop bitterness and malt perception, the key here is the relative levels of Sulphate and Chloride Ions in the final beer. These can be adjusted using Gypsum (Calcium Sulphate), Epsom Salts (Magnesium Sulphate), Table Salt (Sodium Chloride) and/or Calcium Chloride. Care needs to be taken using these salts in the mash, as the Calcium and Magnesium ions will affect mash pH (typically lowering it - might help with your problems). Salts can be added to the boil if necessary. A balance towards Sulphate tends to enhance perception of bitterness and Chloride maltiness.
You can't just assume that your rainwater is free from salts, either. It may be worth while getting it analysed so you know your exact starting point.
The best way to learn about this in depth is to read, and listen to some excellent Podcasts on the subject.
Recommended reading (on the web) is John Palmer's How to Brew in particular chapter 15
http://www.howtobrew.com/section3/chapter15.html. John also has a great spreadsheet for calculating water adjustments
http://howtobrew.com/section3/Palmers_Metric_RA_ver2e.xls.
Recommended Podcasts are:
The Brewing Network - Brew Strong Water Shows I - IV
http://thebrewingnetwork.com/shows/497
http://thebrewingnetwork.com/shows/500
http://thebrewingnetwork.com/shows/508
http://thebrewingnetwork.com/shows/513
The Brewing Network Sunday Session
http://thebrewingnetwork.com/shows/The-Sun...ter-Chemistry-1
http://thebrewingnetwork.com/shows/The-Sun...er-Chemistry-II
Apologies for the less that straight forward answer, but you will find that it's a less than straight forward issue. Hope this helps.
