Acid Model

[gl1800cat]

In the Final Mash pH Adjustments section, there is a drop down for BW Model and MPH 3 Model. What is the difference and which should I use? I see the BW Model gives me a lower adjusted pH. Also, where would you find the acid content of the acidulated malt? I went to Weyermann and looked their acidulated malt and it doesn't list acid percentage. Is there an advantage to using malt over lactic acid?
Thanks in advance!!

 

[BeerSmith]

The BW model is similar to the BNW model which in a nutshell assumes the acid is 100% effective at lowering the pH. The MPH model is based on the work of D. Mark Riffe and others and assumes that the grains provide buffering capacity which reduces the effectiveness of the acid additions in lowering the pH.

So if I have to summarize, I would say that the BW model provides a lower bound on the acid needed in reality while the MPH model provides more of an upper bound. In reality the number may be somewhere between the two models, but it is difficult to say exactly where due to variability in the grains and chemistry involved.

What I do is add a portion of the acid up front to get into the "good" pH range and then add the remainder after I've measured the actual mash pH to make a final adjustment.

Brad

 

[GigaFemto]

Using lactic acid or phosphoric acid gives you more quantitative precision than using acidulated malt. On the other hand, some brewers want to comply with the Reinheitsgebot, sometimes called the German purity law, that doesn't allow for anything except water from a natural source, malt, hops and yeast. In that case you can use acidulated malt and take your chances.

I usually use 88% lactic acid and split the difference between the BW and MPH suggestions. If the amount of lactic acid is too small to measure accurately I will use 10% phosphoric acid.

--GF

 

[gl1800cat]

The BW model is similar to the BNW model which in a nutshell assumes the acid is 100% effective at lowering the pH. The MPH model is based on the work of D. Mark Riffe and others and assumes that the grains provide buffering capacity which reduces the effectiveness of the acid additions in lowering the pH.

So if I have to summarize, I would say that the BW model provides a lower bound on the acid needed in reality while the MPH model provides more of an upper bound. In reality the number may be somewhere between the two models, but it is difficult to say exactly where due to variability in the grains and chemistry involved.

What I do is add a portion of the acid up front to get into the "good" pH range and then add the remainder after I've measured the actual mash pH to make a final adjustment.

Brad

Thanks Brad ... I have used your software for a while now and JUST started paying close attention to the water profile. Thankfully, I have pretty good water straight out of the ground, so little is needed except dialing in the pH (for a Pilsner); maybe a TOUCH of Epsom Salt. See attached ...