Help me learn more from this

[BrewRunning]

So, I have been trying to learn more about treating my brew water and watching my PH. I'm trying to figure out what I did wrong here and how I can correct it next time. I'm making a 5 gallon Imperial Stout, recipe below. I used 60% distilled water and 40% tap. I mashed in with 6 gallons of water, added 3g Calcium Chloride (3/4 tsp) and 4.5g baking soda (1 1/8 tsp) per Bru'n Water. Mash rested nicely at 154 after 15 minutes BUT, measured PH was 7.7. I added 1.5ml lactic acid and waited another 15 min. PH was 7.2. Again added 1.5 ml lactic and waited. PH was 6.6, at this point I quit adjusting.

I added 2.5 ml lactic acid to my sparge water and it hit 5.5 PH.

What should I do differently next time or, did I do something wrong this time? Should I not add the baking soda even though my estimated PH without it was way low?

Thanks for any input!!

Grain bill

14lb 2 row
1lb crystal 60
1lb crystal 120
8oz brown malt
8oz chocolate malt
4ozroasted barley

 

[ajdelange]

I'm guessing that the mistake was adding the baking soda. Situations where you need to add alkalinity certainly do occur but they are, especially where you have appreciable alkalinty in your water, as you seem to, are fairly rare. The data you gave suggest that your tap water's alkalinity is about 3.5 mEq/L (170 ppm as CaCO3).

When making dark beers with water of substantial alkalinity it is best to not rely on spreadsheets but rather test mashes. Next time (or any time) make up a small grist (about a pound or so) in the same proportions as the full grain bill and mash with a couple quarts of warm water (blended with RO as you intend to in the full mash). Check pH at room temperature and let this be your guide as to how much base (if any) or acid you need to add. If pH is way low then try again with some base added and repeat until you get close to your desired target. Scale the addition to the full brew size and you should then land pretty close to your target mash pH when you do the full brew. This should save you chasing the elusive desired pH with acid additions during the actual mash.

 

[BrewRunning]

That makes a lot of sense, thanks! Should I expect the finished beer to be affected by this mistake? If so, to what degree?

Also, I did get really poor mas eff. expected SG was 1.081 I came out at 1.066. Would the high Ph have contributed?

Thanks again!

 

[ajdelange]

It might well have. 6.6 is pretty high. The beer will probably not be ruined by this. In fact it may well be quite enjoyable. After all, home brewers have been making decent beer since well before pH even entered our lexicon. It will definitely not be as good, however, as it could have been.

In No. 2 I said that I was guessing that the problem was adding the baking soda. If we want to apply a little science to the problem (which is why I assume you came to the Brewing Science forum) we can test that guess by looking at the data you collected. The 4.5 grams of baking soda contribute about 4500/124 = 53 mEq of alkalinity as 124 is the molecular weight of NaHCO3. With that much added alkalinity you got a pH of 7.7. The normality of 88% lactic acid is about 11.5 mEq/mL i.e. each mL of it can neutralize 11.5 mEq of alkalinity. Thus the effective added alkalinity with 4.5 grams of baking soda and 1.5 mL of lactic acid is 53 - 1.5*11.5 = 35.75 mEq. This gave you a pH of 6.6. Adding another 1.5 mEq of acid would cancel another 17.25 mEq of the bicarb and give you an effective added alkalinity of 53 - 1.5*11.5 - 1.5*11.5 = 18.5 mEq. This gave you a pH of 6.6. Plotting those three points gives the three open circles on this graph:

Fitting a straight line through those points shows that the relationship between added alkalinity and mash pH for this mash is pretty linear so that extrapolating the fit line to the region of desired pH ought to give an indication as to how much alkalinity you should have added for any desired pH. Suppose you wanted 5.5. The graph shows that you should have added approximately -16.4 mEq of alkalinity (the fit line is mEq = -188.405 + 31.2775*pH). That is +16.4 mEq acid. With lactic's normality of 11.5 that's 18/11.5 = 1.43 mL.

Thus we confirm the suspicion that you should have added less bicarbonate. In fact it appears that you should have added acid instead of bicarbonate. This happens fairly frequently with spreadsheets that have crude models of colored malts based often only on their color (°L) or type. Of course there is also the possibility that you entered data into your spreadsheet in error.

Now this does not guarantee that you can just go out next time and add 1.43 mL lactic acid and no bicarbonate to a grist of the same composition and hit pH 5.5. You may have the same malts but from a different maltster or from the same maltster but a different batch etc. and/or your water's alkalinity may be subject to variation over time. And, while titrating malts or mashes as you effectively have done here is indeed the way to accurately control mash pH that wasn't your intention and so your observations cannot be considered the robust measurements that we would expect if it were your intention. Furthermore, extrapolation outside the range of observation is what we call "bold" extrapolation. The line probably continues as a more or less straight line but we as we do know that malt titration curves are non linear (if not terribly so) we are on slightly shaky ground at pH 5.5.

What it does strongly suggest, however, is that a test mash with 1.43 mL of lactic acid (scaled to the size of the test mash, of course) would be a good place to start.

 

[Silver_Is_Money]

Could part (to perhaps all) of the fault lie in the OP not having input his source waters high alkalinity into the spreadsheet at the onset?

 

[Silver_Is_Money]

I just quickly input the OP's recipe into 'Mash Made Easy', and for straight RO water this recipe (with moderate mineralization) would likely mash straight up at right around 5.4 pH. But with 6 gallons of 170 ppm alkalinity strike water (instead of RO water) at least 4 mL of 88% Lactic Acid (and up to as much as 6 mL) is called for. Admittedly there is a lot of speculation involved here because the analyticals (mineral content and alkalinity) of the OP's tap water is an unknown.

All of this as opposed to being guided into the addition of 4.5 g. of baking soda, which took the pH seriously in the wrong direction.

 

[Silver_Is_Money]

The 4.5 grams of baking soda added 118 additional ppm of alkalinity to the 6 gallons of strike water. The baking soda alone required a tad more than 4.5 mL of Lactic Acid, just to neutralize it, and not to also neutralize the alkalinity present in the tap water.

 

[ajdelange]

Could part (to perhaps all) of the fault lie in the OP not having input his source waters high alkalinity into the spreadsheet at the onset?

Of course there is also the possibility that you entered data into your spreadsheet in error.

I just quickly input the OP's recipe into 'Mash Made Easy', and for straight RO water this recipe (with moderate mineralization) would likely mash straight up at right around 5.4 pH. But with 6 gallons of 170 ppm alkalinity strike water (instead of RO water) at least 4 mL of 88% Lactic Acid (and up to as much as 6 mL) is called for. Admittedly there is a lot of speculation involved here because the analyticals (mineral content and alkalinity) of the OP's tap water is an unknown.

He used 60% RO water. His measurements extrapolated suggest that his mash pH without any addition of acid or base would have come in at a pH of 6.

 

[BrewRunning]

It might well have. 6.6 is pretty high. The beer will probably not be ruined by this. In fact it may well be quite enjoyable. After all, home brewers have been making decent beer since well before pH even entered our lexicon. It will definitely not be as good, however, as it could have been.

In No. 2 I said that I was guessing that the problem was adding the baking soda. If we want to apply a little science to the problem (which is why I assume you came to the Brewing Science forum) we can test that guess by looking at the data you collected. The 4.5 grams of baking soda contribute about 4500/124 = 53 mEq of alkalinity as 124 is the molecular weight of NaHCO3. With that much added alkalinity you got a pH of 7.7. The normality of 88% lactic acid is about 11.5 mEq/mL i.e. each mL of it can neutralize 11.5 mEq of alkalinity. Thus the effective added alkalinity with 4.5 grams of baking soda and 1.5 mL of lactic acid is 53 - 1.5*11.5 = 35.75 mEq. This gave you a pH of 6.6. Adding another 1.5 mEq of acid would cancel another 17.25 mEq of the bicarb and give you an effective added alkalinity of 53 - 1.5*11.5 - 1.5*11.5 = 18.5 mEq. This gave you a pH of 6.6. Plotting those three points gives the three open circles on this graph:

View attachment 551570

Fitting a straight line through those points shows that the relationship between added alkalinity and mash pH for this mash is pretty linear so that extrapolating the fit line to the region of desired pH ought to give an indication as to how much alkalinity you should have added for any desired pH. Suppose you wanted 5.5. The graph shows that you should have added approximately -16.4 mEq of alkalinity (the fit line is mEq = -188.405 + 31.2775*pH). That is +16.4 mEq acid. With lactic's normality of 11.5 that's 18/11.5 = 1.43 mL.

Thus we confirm the suspicion that you should have added less bicarbonate. In fact it appears that you should have added acid instead of bicarbonate. This happens fairly frequently with spreadsheets that have crude models of colored malts based often only on their color (°L) or type. Of course there is also the possibility that you entered data into your spreadsheet in error.

Now this does not guarantee that you can just go out next time and add 1.43 mL lactic acid and no bicarbonate to a grist of the same composition and hit pH 5.5. You may have the same malts but from a different maltster or from the same maltster but a different batch etc. and/or your water's alkalinity may be subject to variation over time. And, while titrating malts or mashes as you effectively have done here is indeed the way to accurately control mash pH that wasn't your intention and so your observations cannot be considered the robust measurements that we would expect if it were your intention. Furthermore, extrapolation outside the range of observation is what we call "bold" extrapolation. The line probably continues as a more or less straight line but we as we do know that malt titration curves are non linear (if not terribly so) we are on slightly shaky ground at pH 5.5.

What it does strongly suggest, however, is that a test mash with 1.43 mL of lactic acid (scaled to the size of the test mash, of course) would be a good place to start.

Wow, thanks for all of that information. Yes, the reason I posted here is because I'm really trying to wrap my head around the sciences behind all of this. I'm starting to understand it a lot better recently but, as you can see, I'm still learning and making mistakes. I'm just hoping to learn from each of the mistakes so I'll do better next time.

You're explanations will help me out a great deal on that. I'll also post screenshots of how I had the spreadsheet set up for this brew (Just to rule out any errors there).

I also believe the biggest mistake was adding the baking soda. Next time I will test mash ahead of time and only add baking soda if the mash PH ACTUALLY tests lower.

Thanks again!!

 

[BrewRunning]

Without the Baking Soda addition the spreadsheet shows an estimated mash PH of 4.98

 

[BrewRunning]

I just quickly input the OP's recipe into 'Mash Made Easy', and for straight RO water this recipe (with moderate mineralization) would likely mash straight up at right around 5.4 pH. But with 6 gallons of 170 ppm alkalinity strike water (instead of RO water) at least 4 mL of 88% Lactic Acid (and up to as much as 6 mL) is called for. Admittedly there is a lot of speculation involved here because the analyticals (mineral content and alkalinity) of the OP's tap water is an unknown.

All of this as opposed to being guided into the addition of 4.5 g. of baking soda, which took the pH seriously in the wrong direction.

Thanks, I posted screenshots above, hopefully that helps shed a little more light on the make up of the tap water used.

Thanks again!

 

[ajdelange]

I believe that in this case you were another victim of the canned profile school. These folk believe that the water makes the beer and there is indeed some truth to that. The lagers of Pilsen are what they are because the deep wells there produce water with very little mineral content. The supposition is that the converse is true: that water with high alkalinity is necessary to produce dark beers because dark beers often originate in places where the water is alkaline. Believers in this often loose sight of the fact that as soon as a hard, alkaline water is heated calcium carbonate drops out so that the water that goes into the mash tun is appreciably less hard and less alkaline than the bore water of the city where the beer in question was originally produced. Thus if you insist on using a profile you should make the salt additions necessary to give the ion contents in the profile (which more or less resembles the water of the bore at the Schloß Sankt Schimmelpreester brewery) and then boil it, dropping much of the hardness and alkalinity so that it now resembles what the good brothers there actually put into their mash tun.

IMO there is little reason to go to considerable trouble to put something in and then take more trouble to remove it. To me it makes much more sense to find out what the stylistic ion (sulfate and chloride) concentrations that do well with this style are and set them using the calcium and/or sodium salts. As people usually don't know at the outset how they like sulfate I often advocate starting with nothing but some calcium chloride (1/2 tsp per gallon RO), brewing the beer and tasting it with and without some calcium sulfate added in the glass. If it tastes better with a bit of CaSO4 then use some the next time you brew this beer. Do the same experiments with other salts too.

 

[ajdelange]

Without the Baking Soda addition the spreadsheet shows an estimated mash PH of 4.98

This, with your measurements, suggests that the spreadsheet is assuming (implicitly or explicitly) that there are 20 mEq more protons in your grist than there apparently are. This is explainable by a difference of as little as 0.05 pH in what the spreadsheet assumes the base malt DI mash pH to be and what the actual base malt pHDI is. This is not to say that the error is in the base malt. It could be in any of the malts or a combination of them. I think this spreadsheet lets you tweak color. Try zeroing the baking soda, adding the 1.43 mL of lactic acid and then tweaking the colors of some of the malts until the baking soda requirement goes to 0. You should now have something that sort of resembles the buffering of this mash.

 

[Silver_Is_Money]

By inputting your specifics (including the water, 40% tap and 60% RO) from the snapshots you provided above, my 'Mash Made Easy' spreadsheet shows this batch doughing in and mashing at a pH of roughly 5.43 straight up, without any baking soda or lactic acid additions. Allowing for a broad safety margin of 0.2 pH as wiggle room for error, that would still leave you mashing at an acceptable pH of 5.23.

4.98 pH seems suspiciously low. Is that the indication from your spreadsheet after lactic acid addition(s)?

As an aside, are you sure your 2-Row base malt is 3L, and not the more typical 1.8L to 2L?

 

[Silver_Is_Money]

Minor nitpicking, but Brown Malt is not a Crystal malt. Crystal malts have more acidity, color for color, (and with respect to a mash pH target of 5.4) than the other malt options (speaking in regard to my own spreadsheet here, as well as for hard maltster data), but at only 8 ounces this is more than likely a moot point.

And a 2-Row type base malt at ~3L will generally be less basic (with respect to a target mash pH of 5.4) than a 2-Row base malt at ~1.8L.

 

[Silver_Is_Money]

If BrewRunning ever makes this recipe again, it would be highly interesting (as well as helpful to mash pH software developers) to see where the mash pH actually falls, for the case of no other recipe or water ratio changes, sans that no baking soda or lactic acid are to be added, and with the pH sample taken 20 minutes into the mash, along with the sample being cooled to room temperature prior to pH measurement. Stirring extremely well to uniform the mix of malts and added minerals after doughing in, and then stirring again right before drawing the sample, would also be a requirement.

I would be interested in knowing more with regard to the specifics of the 2-Row used in this batch. European 2-Row base malt is often well more basic (caustic) with respect to a nominal mash target of 5.4 pH than would be a North America sourced 2-Row of the same Lovibond color. It is possible for the DI Mash pH of low colored 2-Row base malts to vary from about a low of pH 5.5 to as high as pH 6.1, and with 14 Lbs. of base malt in this grist, the final measured mash pH would be highly impacted by the two potential extremes of the DI Mash pH for this base malt.

 

[BrewRunning]

If BrewRunning ever makes this recipe again, it would be highly interesting (as well as helpful to mash pH software developers) to see where the mash pH actually falls, for the case of no other recipe or water ratio changes, sans that no baking soda or lactic acid are to be added, and with the pH sample taken 20 minutes into the mash, along with the sample being cooled to room temperature prior to pH measurement. Stirring extremely well to uniform the mix of malts and added minerals after doughing in, and then stirring again right before drawing the sample, would also be a requirement.

I would be interested in knowing more with regard to the specifics of the 2-Row used in this batch. European 2-Row base malt is often well more basic (caustic) with respect to a nominal mash target of 5.4 pH than would be a North America sourced 2-Row of the same Lovibond color. It is possible for the DI Mash pH of low colored 2-Row base malts to vary from about a low of pH 5.5 to as high as pH 6.1, and with 14 Lbs. of base malt in this grist, the final measured mash pH would be highly impacted by the two potential extremes of the DI Mash pH for this base malt.

I will most likely do this recipe again soon. I plan on brewing another batch and fermenting on top of the yeast cake from this batch. I will definitely post an update on that batch. I will also try to get better information on the grains used next time. I usually just ask for "2-row" from the LHBS and never really paid any attention to what I was actually getting.

Thanks again for all of the input in this thread. It has helped a lot.