Now that I finally brewed an awesome extract brew (Tasmanian devil pale ale)…I kinda want to try some partial mash brews. Currently using all distilled water…but is there enough malt extract in partial mash to make up for the lack of minerals in distilled?
Engineers say KISS. Keep It Simple, Stupid.
Start with tap water.
Don’t fix problems you don’t have.
The reason I ask is because all my 1g batches with tap water had twang 
Chlorine/chloramine in your tap water could be one source of “twang”, so using campden tabs should help.
The need for minerals in brewing water is overblown. Malt provides most of the mineral content that the yeast need to perform effectively. There are a few that are helpful in water: zinc and copper. However, they are only required at really low concentration. Calcium is another one that is helpful for a couple of purposes, but calcium is NOT a requirement.
Your approach of continuing with distilled water for brewing is OK, but you may want to figure out what mineral additions you might want to add so that the beer isn’t too bland. When you start with extract, the mineral content of the maltster’s water is already in there. Typically, that mineral content is low. For some beer styles, you may want a little more of certain mineral salts to help spice up your beer flavor to produce the result you want.
With respect to the helpful zinc and copper ions, use a commercial yeast nutrient and you should be covered. Including a length of copper tubing in your brewing system also helps supply copper.
Use distilled.
I throw my copper wort chiller in during boil and use yeast nutrient 
. Thanks guys!
This thread has me a little confused. When you do a partial mash you get a portion of the wort from grain. If you use distilled water to do the mash will you still get proper conversion and good efficiency without adding minerals back in? Is it ok to do an AG batch with distilled water only?
Paul
Hmm… I had to think about this. The answer is a little complicated, as it depends on your grist.
First of all, ideal mash pH is 5.3, with an acceptable range of about 5.2 to 5.5. Anywhere in there is good.
I have read in Designing Great Beers by Ray Daniels (excellent book) that a mash of 100% base malt (e.g., American 2-row pale malt, Maris Otter, Pilsner malt, etc.) in distilled water should give you a mash pH of 5.8, which is actually too high. So if you have all 100% base malt in the mash, and nothing else, it could be problematic. If you have just a tiny bit of specialty malt, less than 10%, this could also be problematic. What sorts of problems? Tannin extraction and astringency, in addition to mash efficiency.
In general, if you have more than about 15% specialty malts (i.e., dark roasted or crystal malts) in your mash, then mash pH will take care of itself, lowering down to 5.2 to 5.4 from the acidity of the specialty malts alone. Same goes for reasonably low to moderately hard water. Very hard or alkaline water would need even more specialty malts and/or salts or acid to bring mash pH down. Not sure what your mash pH is? Spend a couple bucks on those cheap little pH strips. They aren’t easy to read but they will give you a rough ballpark reading. Or just use distilled water plus the guidance here, knowing the baseline that 100% base malt in distilled gives you 5.8.
If your mash grist is more than about 30-35% specialty malts without base malt, then mash pH in distilled water could actually turn out too low, below about 5.1, which could be problematic in the other direction. Resulting beer could turn out quite tart or acrid in flavor, and again you may see a decline in efficiency.
So… long story short, if you have a good mixture of base malt and specialty malt in your partial mash, with approximately 70-85% base malt and a little bit of specialty malt, then distilled water will be just fine to mash in. Otherwise it would indeed be wise to strike a better balance between base malt and specialty malt to ensure the right mash pH. If you’ve got mostly specialty malts and little base malt, maybe you just want to ditch the base malt and do a standard extract recipe plus steeping the specialty grains. If you have mostly base malt, throw in 15% crystal or roasted barley or something to bring your mash pH down, and you’ll have no worries.
That help? 
:cheers:
How 'bout just tossing some of the DME/LME in with distilled water? If it has all the minerals you need, it should improve the properties of distilled water for mashing. Plus, the enzymes from the base malt should improve the fermentability of the extract. Maybe not make it super high gravity, as that would hurt the efficiency, but a little bit might help.
That’s an interesting idea as well, porkchop. Keep in mind that whatever extract you throw into the mash would become partially absorbed by the grains, slightly reducing the total amount of extract you will see in the preboil/postboil. But it should be very slight, maybe only lose 0.001-0.002 points of gravity.
Isn’t all this getting a bit deep for an OP, who says he’s just starting to Partial Mash?
I’m not disagreeing with anything that’s been said. It’s just they are all advanced-level answers to an intro-level question.
I stick to my original suggestion. Try the PM with the tap water first, although I’m with Voodoo on The campden suggestion.
Ah… the ways of the interwebs…
I intended no disrespect. Apologies if I came off troll-ish.
