Distilled Water and Mash Efficiency

Hey folks I recently moved and my tap water does not taste very good so I started using distilled water to brew with. I have noticed that my efficiency is not quite as high as it used to be, around 67% vs 75% before using tap water. I think next time I will try spring water, but I am curious to know if using distilled water with no additives will cause issues like this?

I read something about the enzymes needing the minerals to convert efficiently. I'm sure someone else will jump in with more details but spring water is definitely preferred over distilled or reverse osmosis water for all grain.

It's not about having NO minerals, it 's about having the PROPER minerals in the PROPER range for the style and color of the beer you are trying to brew.

Water chemistry is maybe one of the most complex topics in brewing besides yeast. To keep this not too technical I'll just summarize some major points that should help.

Using distilled or RO water solely for AG brewing is actually detrimental to your beer. Many think spring water is better but in actuality it may be just as bad for the opposite reason depending on the source. That reason is that minerals in the water are needed for proper conversion efficiency, taste and yeast health. Distilled water has 0 minerals so you are really not getting all you can out of your beer. On the other hand some spring water may be too high in certain minerals (Mg, Ca, etc.) so certain off flavors may show up in the brew (harsh bitterness for example). If you want to use spring water make sure you are able to get a water analysis sheet from the company you use and verify it is a good profile for brewing.

I recommend downloading John Palmers spreadsheet from howtobrew.com to help you determine a good water profile and how one should change it. I also HIGHLY recommend downloading the 4 part Brewstrong podcast on water chemistry to gain a basic knowledge of what waters role in brewing is.

Since you are already willing to use distilled water for brewing, a good way to make your water perfect is to build your own profile from distilled using various salts and minerals, easily available from homebrew stores, so you can have a customizable profile perfect for the style you are brewing. You can do this by using the water spreadsheet from John Palmer.

Do you know what the mineral content of your tap water is? It could be that you just need to carbon filter your water.

If you are going to use distilled, follow cellardoor's advice and read up on Palmer's teaching on brewing water chemistry.

JKoravos said:

Do you know what the mineral content of your tap water is? It could be that you just need to carbon filter your water.

If you are going to use distilled, follow cellardoor's advice and read up on Palmer's teaching on brewing water chemistry.

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Nope, no idea on the content, its a small community well that is managed by a third party for the neighborhood. I thought about running it through a filter as well, but I can tell that the water is hard also (it leaves deposits), so I dunno how much I want to mess with it.

I downloaded the spreadsheet but have not had time to read through it all the way, I will probably try to go that route. The few brews I have made with the distilled water have tasted really good and fermented very well, just a tad low on efficiency.

Thanks for the info everyone.....I am definitely going to watch those podcasts so I can become a little more educated on the subject.