Using 5.2 with Bo Pils

OK, I have looked all over in researching my first Bo Pils for this info. The recipe I have formulated is from a few sources but is calling for 10% Acid malt to drop the PH when using a high percentage of RO water. I am concerned that 10% will come through in the flavor and that is NOT what I want. I don't have any real experience with water chemistry but I used a calculator to come up with 85% distilled and 15% tap water based on my local water report to get pretty dang close to Bo Pils water without salt additions.

Now, I read that Acid malt will drop PH .1 units per 1% of grist. My local water PH is 7.7 (average) and distilled is around that as well, so even using 10% Acid malt won't get me down down to 5.2 , and I am definitely not going 25%.


Soooo, the question is: If I use the 5.2 PH stabilizer stuff, will it throw off any of the other minerals necessary for a Bo Pils. Ingredients are neutralized, so I don't think so, but unsure. Have any of you done it with good or bad results? Am I figuring correctly here as far as dropping my PH? Is there another better way to control PH? I am hoping to simply do an 85-15% distilled to tap ratio and dump in some 5.2 and call it good. No Acid malt preferably. What do ye think?

Thanks All

Don't use the 5.2.

10% acid malt is too much for a Boh pils (or for any pils for that matter) so that recipe is suspect to me. I don't know what your local water mineral profile is, but using only 15% and the rest distilled....I'd probably use 100% distilled and then follow the water primer. Definitely use some acid malt, 3% is great and provides a flavor addition as well. 10% is too much. Go with the 3% acid malt, use a little calcium chloride, 100% distilled, and then mash/brew as usual, you won't be disappointed.

I said it at the beginning, and I'll say it again. Don't use the 5.2.

There have been a ton of threads about that 5.2 stuff in the brew science forum. Most of them say the stuff is completely useless. I threw mine away after reading them.

You're better of taking the money you were going to spend on the 5.2 and buying 10 gals of RO water. You should be able to use a 3% max acid malt addition along with about 1/2 tsp of CaCl. This should get you close to the correct pH and maintain a soft water profile. By the way, a 10% acid malt addition seems really high, even for hard water.

You want the mash pH to be 5.2, not your water. Just the act of mashing your grain ought to lower the pH fairly close to the target range, so you really shouldn't need anything near 10% acid malt. I would try something like 1% and see how that works.

I just read that recipe again and it's an extract recipe, so not sure what they were going for with the acid malt - obviously just a flavor addition. Maybe that .75 lbs acid malt adds the right "tang", not sure. Stick with the water primer.

To add, the pH of your tap isn't all that crucial, it's the buffering capacity of the minerals it contains that are of concern. The pH of distilled is essentially meaningless is it really has no buffering capacity, so you can't just compare pH of distilled and the pH of your local water - it's not an accurate or meaningful comparison.

The distilled water with calcium chloride gives you a known starting point, mash your light grains (and the acid malt) with it and it'll get you in the ballpark on pH.

What? It's an extract recipe? Then there should be no water adjustments.


But if it's really extract, why is it posted in the AG forum?

I am not referencing the recipe really, just the information above it.

GrizBrew said:

I am not referencing the recipe really, just the information above it.

Click to expand...

Can you post the recipe?

Just because you're starting off with water of pH 7.7, doesn't mean you have to add 25% acid malt to get to 5.2. Adding grain to the mash (as weirdboy posted above) brings your mash pH very close to being within range. The act of mashing acidifies your starting water. The "problem" with light grain bills is that they don't quite get it there without a little help, this is where the acid malt comes into play. Although you do get variability in pils malts - from maltster to maltster, from lot to lot from the same maltster, and from season to season - it's been shown (probably mostly by AJ, the author of the primer - thanks a million times for this) that the mash pH is pretty predictable when you start with a known water profile (the distilled with a little calcium chloride in the primer). To get any closer, you need to utilize a pH meter and check your mash every time.

My actual recipe is:


OG: 1.059
IBUs: 41.8
Color: 4.9 SRM
ABV: 5.8%


24 lbs Floor Malted Bohemian Pilsner
2 lbs Munich
1 lbs Acid Malt (adjusted per your recommendations)
1 lbs 8.0 oz Cara-Pils
3 oz Saaz [3.00 %] - Boil 75.0 min
3.5 oz Saaz [3.00 %] - Boil 60.0 min
3.5 oz Saaz [3.00 %] - Boil 30.0 min
3 oz Saaz [3.00 %] - Aroma Steep 10.0 min
3 oz Saaz [3.00 %] - Aroma Steep 0.0 min
2.0 pkg Urquell Lager (Wyeast Labs #2001)


This is my water profile entered into the calculator referenced above.

GrizBrew said:

This is my water profile entered into the calculator referenced above.

My actual recipe is:


OG: 1.059
IBUs: 41.8
Color: 4.9 SRM
ABV: 5.8%
24 lbs Floor Malted Bohemian Pilsner
2 lbs Munich
1 lbs Acid Malt (adjusted per your recommendations)
1 lbs 8.0 oz Cara-Pils
3 oz Saaz [3.00 %] - Boil 75.0 min
3.5 oz Saaz [3.00 %] - Boil 60.0 min
3.5 oz Saaz [3.00 %] - Boil 30.0 min
3 oz Saaz [3.00 %] - Aroma Steep 10.0 min
3 oz Saaz [3.00 %] - Aroma Steep 0.0 min
2.0 pkg Urquell Lager (Wyeast Labs #2001)

Click to expand...

I can't see your water profile. 1 pound of acid malt is too much. Use no more than 3%, but preferably less. I'd go with 100% RO water and enough calcium chloride (only) to get you 50 ppm of calcium. Some people do use a little gypsum with BoPils, but I don't care for sulfate in the water with Saaz hops. That alone should get you to a proper mash pH of 5.4ish. Check with a water calculator spreadsheet (I like bru'nwater) to guestimate your mash pH, though!


Edit- now I see the water profile! I can't see the acid additions for the acid malt or the projected pH, though.

I would probably go down to 0.75 lbs of acid malt. I usually look at my total grain bill weight minus the acid malt addition, and apply the percentage to it. In your case it looks like 27.5 lbs, 3% of that is about 13 ounces. You're probably OK to leave it at a pound too. Add some calcium chloride as well. It's my understanding that the mash usually has all the minerals it needs - except for the calcium.


I like the recipe. Make a HUGE starter though with those 2 packages of yeast, I'm assuming 10 gallons on this. 5L starter on a stir plate if you can. Pitch when the wort is cold (at or below ferm temps). Sorry - branching out to areas you didn't ask about....

That's cool. Yes, I planned 2- 5 Liter Starters, one for each carboy. It is a 10 gallon batch. I am actually gonna mash 1/3 more and separate another 5 gallons to a different kettle and use Nelson Sauvin for that, to end up with the same IBUs. I think that could make a lovely Bo Pils

A pound of Saaz. That'll be good.
Don't be afraid of the acid malt, just don't overdo it either.
Follow up in a month or two when it's done. I bet you'll be pleased.

My recipe is vary close to yours except for the Munich and cara. I use Weyermanns dark floor malt instead of Munich and no cara. The malt isn't as aggressive as Munich. I use 2 pounds of sauer malt. My grain bill is 27 pounds and run off 18 gallons at 1053. Any more and the pH rises. My sparge water is 7-7.2. The sauer malt with the floor malt won't be detected what so ever in the flavor. I decoction and it takes about 2 hours using 7-7.2 pH RO with some minerals to get to 5.1-5.3 in the main mash with Weyermanns floor malt. I use Budvar 802 with a 5 litre starter at high krausen. Urquel finishes sweeter than I like. Dough in with water hot enough to get the mash at 100 degrees. Weyermanns floor malt is kilned at a low temp and has phytase, unlike well modified. The phytase will lower the pH along with the sauer malt at 100F. I don't know what process you'll use, but your recipe with a tri decoction makes a great beer that has stability and shelf life. I draw the 1st decoction when the main mash is at 5.6. I skip the acid rest in the 2nd decoction. The main mash will continue to drop in pH. By the time I get to conversion the main mash is 5-1-5.3. After the phytase is denatured, the sauer malt does the rest. Going through all the pH and temp ranges beef up the beta and alpha and adds minerals and nutrients that help yeast and allow the beer to be stable to Lager. The 100F rest will help solubilize hard starch stuck in the husk. Next time try the same recipe using the dark floor malt, it makes a great beer, too. I use 3 malts, Wyermanns light and dark floor malt and Weyermanns sauer for Pils and Lager. Years ago I was able to get Budvar floor malt, it was 20 percent modified and made great beer. It had to be decoctioned. Just can't get it any more. I can change the color and taste by varying decoction temps and boil length of decoctions along with conversion temps. I use 1 pound of either Saaz or German Hallertau. Usually 6-8 oz in the boil after hot break, 3 oz in the hopback, the rest at flame out. Go for it. You won't be disappointed.

StoneHands said:

Don't use the 5.2. 10% acid malt is too much for a Boh pils (or for any pils for that matter) so that recipe is suspect to me. I don't know what your local water mineral profile is, but using only 15% and the rest distilled....I'd probably use 100% distilled and then follow the water primer. Definitely use some acid malt, 3% is great and provides a flavor addition as well. 10% is too much. Go with the 3% acid malt, use a little calcium chloride, 100% distilled, and then mash/brew as usual, you won't be disappointed. I said it at the beginning, and I'll say it again. Don't use the 5.2.

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Thanks for that water primer. I just haven't really given water chemistry nearly enough thought. There seem to not be too many styles particularly dependent on it but Bo Pils is definitely one of them. I am ready to step up my brewing game to learn more about PH and water chemistry and how controlling them may take my beer up another notch. I appreciate all of you chiming in here.

VladOfTrub said:

My recipe is vary close to yours except for the Munich and cara. I use Weyermanns dark floor malt instead of Munich and no cara. The malt isn't as aggressive as Munich. I use 2 pounds of sauer malt. My grain bill is 27 pounds and run off 18 gallons at 1053. Any more and the pH rises. My sparge water is 7-7.2. The sauer malt with the floor malt won't be detected what so ever in the flavor. I decoction and it takes about 2 hours using 7-7.2 pH RO with some minerals to get to 5.1-5.3 in the main mash with Weyermanns floor malt. I use Budvar 802 with a 5 litre starter at high krausen. Urquel finishes sweeter than I like. Dough in with water hot enough to get the mash at 100 degrees. Weyermanns floor malt is kilned at a low temp and has phytase, unlike well modified. The phytase will lower the pH along with the sauer malt at 100F. I don't know what process you'll use, but your recipe with a tri decoction makes a great beer that has stability and shelf life. I draw the 1st decoction when the main mash is at 5.6. I skip the acid rest in the 2nd decoction. The main mash will continue to drop in pH. By the time I get to conversion the main mash is 5-1-5.3. After the phytase is denatured, the sauer malt does the rest. Going through all the pH and temp ranges beef up the beta and alpha and adds minerals and nutrients that help yeast and allow the beer to be stable to Lager. The 100F rest will help solubilize hard starch stuck in the husk. Next time try the same recipe using the dark floor malt, it makes a great beer, too. I use 3 malts, Wyermanns light and dark floor malt and Weyermanns sauer for Pils and Lager. Years ago I was able to get Budvar floor malt, it was 20 percent modified and made great beer. It had to be decoctioned. Just can't get it any more. I can change the color and taste by varying decoction temps and boil length of decoctions along with conversion temps. I use 1 pound of either Saaz or German Hallertau. Usually 6-8 oz in the boil after hot break, 3 oz in the hopback, the rest at flame out. Go for it. You won't be disappointed.

Click to expand...

Yup, triple decoction planned for this. I would love to try some of that dark floor malt. Next time! I have seen that and thought about a Czech Dunkel as well. You ever made one? Thanks for that mash schedule and enzyme breakdown. I think I need to pick up a PH meter. That is interesting that you pay more attention to PH than temperature and time when doing your decoctions. It makes sense that it would be a more accurate way to judge conversions. I am always learning!

A Boh Pils is one of the few places I would recommend starting off with RO or distilled water; the original Pilsen water is extremely soft, so trying to match it from purified water would require only some calcium additions, with CaCl2 being preferred over gypsum here. I am lucky in this regard, as Lake Lanier water (which is the source for Atlanta and it's environs) is almost as soft as Pilsen, so I have few problems with paler brews (though I do need to add chalk for darker ones).

Griz. Good to see that you're doing a decoction. If you go to Weyermanns website and look at their recipes, you'll notice that they use various temp rests. I use their dark malt for Bock. It's a great malt. I make German Ale with their light floor malt and decoction. When using Weyermann floor malt, there is no brewing method that will give you the quality and quantity of extract as a tri-decoction. Here's how I brew using your recipe. I dough in with cold water at 1 qt/lb and let it rest an hour. This allows the water to get into the grain and soften the hard starch. Then, I fire the mashtun to hit 100F. After a half hour I check pH. If pH is 5.6, I pull the 1st decoction (4 gallons of heavy mash) and run the temp to 125F. The main mash will still be in the acid rest, pH will continue to drop. I rest the decoction at 125 for 20 minutes. Then run the temp to 148 and rest for 30 minutes. Then run the temp to boiling and boil until the mash becomes "slick". That's when all the strarch has burst and protein gum has been boiled out. Then add the decoction to the main mash to go from 100F to 125F. Soon as the main mash is mixed well, pull the 2nd decoction (four gallons of heavy mash). Go right to 150F and rest for 30 minutes. (Becareful not to scorch the mash during the decoctions). You skip the protein/albumin rest in this decoction. The main mash will be in a protein/albumin rest and at the higher end of the phytase temp band. During the rest myo-inositol and albumin will be produced. Then run the decoction to boiling and boil till the mash gets "slick". You'll know what I mean by slickness when you get there. Then add the boiling decoction to the main mash to hit 153 to convert. Add another .25 qt/lb of hot water to thin down the mash. It will help with conversion. By this time the main mash pH will be about 5.1-5.3. Becareful with the water treatment. The mash can drop to 4.8 pH. That's OK but real, real close to the point of getting into trouble. Go light on the chemicals. After conversion pull the 3rd decoction of mostly liquid and boil it for 15 minutes and dump it in the main mash. You won't have enough liquid to hit mash out temp so add some boiling water to hit 168-170F or fire the tun. You may need to add some boiling water to raise mash temps throughout the process, too. Unless you have a fired mashtun. Once the main mash is at temp, add sparge water to cover the false bottom and slowly dump the mash into the lautertun, give it a good stir and let the bed settle. Depending on how the lautertun retains heat, 200F water may be needed for sparge to keep the mash temp at 170 and sugars fluid. You will notice a layer of "mud" on top of the grain bed. Try not to disturb it during sparge. If you don't have a pH meter run off until you hit a gravity of 1010-12 at sample temp 60F and stop. Once the bottom of the boiler is covered with wort add .15 oz of hops and fire the boiler. The hops will keep the hot break from overflowing the boiler by reducing surface tension. It's an old German trick that allowed the brewmaster to get more wort in the boiler without boil over. Adding 2 oz of crushed black malt will do the same thing. After hot break add the bittering hops. After the wort is cooled, let it rest an hour or so and dump the trub, aerate and add the yeast...If you alter the protein/albumin rest temp, you will need to alter the conversion temp. The higher the protein/albumin rest temp, the higher the conversion temp should be and vice versa. Stick with 125F protein rest it's close to center. Converting at 153 is the center of beta and alpha temps. Brew on, you'll do fine. After a few batches you'll get every thing dialed in.

Thanks Vlad! All great info. I will try this type of decoction and see how she turns out. I use a HERMS system and fly sparge but temps are easy to hit if the decoction doesn't get me there and I always get great efficiency with decoction mashing.

I typically brew lagers in the Spring and always incorporate decoctions. This last year I tried to only do single decoctions and it really showed in my beer. It makes for a very long brew day but I think decoction mashing is most definitely worth it. Moving from 3 or 4 lagers a year to six or 7 this year with a fall brewing is gonna really give me a workout. I suppose I could use to work off a few of these barley pounds though.