pH/Mineral content for Partial Mash

[JPrather]

Hey all, I'm getting ready to do my first partial mash. (~5 gal Altbier batch using 3lbs Munich/1lbs specialty grains/3lbs DME (Briess Pilsen). Thusfar I have used RO (reverse osmosis) water exclusively with Extract batches, with good results.

I'll be doing a partial mash with 1.375qt/lb with a ~3-3.5 gallon boil and 2.5-3 gallons of top off water.

I've done a bunch of reading on this, and there seems to be some conflicting opinions. So, I have two basic questions:

1) Mineral Content - Some people claim that RO/Distilled/etc water isn't sufficient for mashing, while others claim that mineral content is only important for yeast health, and not necessarily for the mash itself. I also understand that the reason RO water works fine for extract batches is that extract contains the necessary mineral content.

Will using only 3lbs of DME be sufficient to cover my mineral needs (using RO), or should I consider other water sources or mineral additions for the mash and/or top off water?

For reference, the water profile for my tap water is as follows:

Ca+2 = 15
Mg+2 = 5
Na+ = 5
Cl- = 16
SO4-2 = 4
Alkalinity = 50 (HCO3)
pH = 8

I also have access to the normal spring and mineral water sources sold at supermarkets, etc., if need be.

2) Mash pH - The pH of both my local water and RO water is ~8. Using the brewersfriend calculator, with 4lbs of grist using 1.375qt/lb of mash water and a little less sparge water, I get a calculated mash pH of 5.38. Can I assume that I will be okay using any combination of RO and/or tap water without having to make any pH adjustments?

Going with just RO water would be easiest for me, but I can use any combination of RO/tap water/spring/mineral water if needed. I've seen people recommend tap water for the mash, and RO for the top-off water as a good method for partial mashes.

Any comments/suggestions/thoughts are appreciated. Thanks in advance!

 

[Pie_Man]

1 - Mineral content can have impacts on both the mash pH and yeast health. Certain minerals raise or lower your residual alkalinity and thus impact your mash pH. And some minerals (mostly calcium, I think) also have an impact of yeast health during fermentation.
2 - Personally, I would stick to the water sources that you know, like your tap water or RO water, or a blend of the two.

Personally, I would keep things simple on your first partial mash and play around with your water profile at a later time. Regardless, I highly recommend reading the water primer on HBT, downloading and using the Bru'N water spreadsheet, and listening to a few podcasts on water. The Beersmith podcast recently did two water shows that are informative (you don't need Beersmith software to listen to the podcasts). There is also a four part water show from Brew Strong on the Brewing Network.

 

[mabrungard]

While RO and distilled water are ideal for extract brewing, having a bit of calcium in the water for a partial mash is wise. It helps on many levels. With that said, your tap water is a GREAT starting place for brewing. All ion levels are very modest. The main concern is that you will have to acidify a bit to knock that alkalinity down for your pale beers and your sparging water. No need or desire to use anything but your tap water for mashing! You are fortunate.

 

[JPrather]

Thanks a bunch for the responses guys. I was listening to the Brew Strong shows, I'll def. check out the Beersmith one.

I thought my tap water profile looked pretty good, It's good to know that I can use it for mashing. I'll probably end up using some combo of tap water and RO for this considering the mineral content of DME and the need for lower alkalinity sparge water.

Thanks again!