Statistical significance of mash pH estimates?

[ajdelange]

The Riffe paper was getting quite a bit of attention here recently. In it he proposes getting malt buffering information by the use of a "fiduciary" malt that is one whose buffering is known. Sodium bicarbonate is a substance whose buffering properties are known in detail. It can, thus, be used as a fiducial malt. We could get the entire buffering curve were he to make multiple measurements but we are only imposing on him to make one.

 

[hopjuice_71]

No. It doesn't. One of the reasons pH is on a logarithmic scale is that things in nature respond logarithmically. 0.2 pH will make very little difference in efficiency but it can make quite a difference in flavor and that's why brewers track it.

So, this partly computes for me. I've spent a career researching enzymes similar to barley amylases and enzymes in this class have broad pH optima. The barley amylases retain >90% of their activity over a pH range of ~4.5 - 6.5, so the claims of efficiency and FG changing with mash pH have never computed for me. The studies I have seen on this don't statistically back up the claims either. I thought, however, that perhaps the favours of the beers may be affected by the mash pH and that is why many people seem to agonize over pH so much. However, when I have looked into this, the sensory data I have seen (not much in truth) is pretty weak and did not convincingly link mash pH to strong impacts on flavour.

I would really appreciate it if someone could point me to some good primary literature on studies where mash pH impacts the quality of the final product. I tend to pay attention to mash pH but this would help justify my continued attention to it.

Cheers

 

[CodeSection]

My belief is that what we are attempting to replicate is actual mash conditions via which to derive DI mash pH.

You might want to do two sample procedures and measurements, one using A.J.'s criteria, and one using mine, to determine if there is a difference.

The baking soda additions (and pH's) come after measuring the first (or DI) pH. The subsequent baking soda pH's are needed to establish the titration factor(s).

The Riffe paper was getting quite a bit of attention here recently. In it he proposes getting malt buffering information by the use of a "fiduciary" malt that is one whose buffering is known. Sodium bicarbonate is a substance whose buffering properties are known in detail. It can, thus, be used as a fiducial malt. We could get the entire buffering curve were he to make multiple measurements but we are only imposing on him to make one.

I have no problem performing both methods with different grain bills and mash tempts. I was understanding to add the sodium bicarbonate on the second procedure and take a pH reading at 30 minutes as well as at 60 minutes.

To be clear, only add the 200g of sodium bicarbonate AFTER taking the pH reading at 30 minutes?

 

[ScrewyBrewer]

The baking soda additions (and pH's) come after measuring the first (or DI) pH. The subsequent baking soda pH's are needed to establish the titration factor(s).

I haven't had time to read Riffe's latest paper yet. Can you briefly describe the subsequent pH testing process... the number of grams, etc.?

 

[ScrewyBrewer]

I have no problem performing both methods with different grain bills and mash tempts. I was understanding to add the sodium bicarbonate on the second procedure and take a pH reading at 30 minutes as well as at 60 minutes.

To be clear, only add the 200g of sodium bicarbonate AFTER taking the pH reading at 30 minutes?

I highly doubt we'd be adding 7 ounces of baking soda into a mash made from 80g of malt and 200ml of water.

 

[Silver_Is_Money]

I haven't had time to read Riffe's latest paper yet. Can you briefly describe the subsequent pH testing process... the number of grams, etc.?

I believe A.J. came up with this, not D.M. Riffe.

 

[Silver_Is_Money]

I highly doubt we'd be adding 7 ounces of baking soda into a mash made from 80g of malt and 200ml of water.

I thought A.J. mentioned a pinch. Milligrams perhaps?

 

[CodeSection]

Please take a reading at 25 - 30 minutes. Nothing wrong with taking another at 60 too but what we need is the 30 minute reading.

And if you are really interested in helping out repeat the process with 200 mg of sodium bicarbonate added. This will give us the buffering (equally as important as the mash pH) using the Riffe method but with sdium bicarbonate as the 'fiducial malt'.

I highly doubt we'd be adding 7 ounces of baking soda into a mash made from 80g of malt and 200ml of water.

I thought A.J. mentioned a pinch. Milligrams perhaps?

My bad, 200mg of sodium bicarbonate. Still need to know when to add ~ a separate 30/60 minute procedure or just after the first 30 minute pH reading.

 

[Silver_Is_Money]

The baking soda addition(s) are all A.J., so I can offer no "specific" help as to when to add them. I can only add that once the mash is over, it would seem intuitively (to me at least) that the baking soda can be added anytime post the DI_pH reading.

 

[ajdelange]

. I thought, however, that perhaps the favours of the beers may be affected by the mash pH and that is why many people seem to agonize over pH so much. However, when I have looked into this, the sensory data I have seen (not much in truth) is pretty weak and did not convincingly link mash pH to strong impacts on flavour.

I would really appreciate it if someone could point me to some good primary literature on studies where mash pH impacts the quality of the final product. I tend to pay attention to mash pH but this would help justify my continued attention to it.

What I would suggest you do is brew the same beer with mash pH of 5.6 - 5.7 and then again to 5.4 - 5.5. I cannot predict what you will experience but I do know what I experienced. As a consequence I started recommending that people control pH. The gentlemen that, IMO, expressed what happens best said "all the flavors seemed brighter".

 

[ajdelange]

To be clear, only add the 200g of sodium bicarbonate AFTER taking the pH reading at 30 minutes?

Make that 200 mg (0.2g) and you've got it.

 

[ajdelange]

I haven't had time to read Riffe's latest paper yet. Can you briefly describe the subsequent pH testing process... the number of grams, etc.?

A malt is characterized by first measuring the pH of a sample of it mashed in DI water and then repeating with water plus certain amounts of acid or base and measuring the pH of those mashes. A table then can be constructed of mEq acid added per unit weight of malt (base additions are represented as acid deductions i.e. by negative numbers) vs pH with. We usually use sandardized acids and bases for this but Riffe thought that too hard and prposed using a malt with known titration curve instead. He never gets into exactly how to do this but it is quite straight forward - just a lot more difficult to do than working with standard acids/bases.

Standard acids and bases are very easy to work with because the acid added is just the mL aded times the normality of the acid and the acid removed is just the normality of the base solution times the number of mL of that added. We equally well know the "normality" of sodium bicarbonate as a function of pH and so can use it instead of standardized base. It' normality at pH is w*(1 - QAcid(pH, 6.38,10.38))/84.

 

[ajdelange]

My bad, 200mg of sodium bicarbonate. Still need to know when to add ~ a separate 30/60 minute procedure or just after the first 30 minute pH reading.

The baking soda addition(s) are all A.J., so I can offer no "specific" help as to when to add them. I can only add that once the mash is over, it would seem intuitively (to me at least) that the baking soda can be added anytime post the DI_pH reading.

At the begining of a second, separate procedure.

 

[CodeSection]

@Silver_Is_Money and @ajdelange , I haven't forgotten about you guys and my promise to take pH readings. Work and life events have taken up more time than anticipated.

Hopefully, this Friday I will be able to get off work early and will be able to block out 2-3 hours and conduct the tests later in the day/night.

 

[CodeSection]

@Silver_Is_Money , @ajdelange , @ScrewyBrewer , well I thought I could get off four hours earlier on Friday. I ended up working three hours longer. Tonight, I was able to perform the following:

First Test: 50g of Briess Rye Malt with 100 ml of distilled water mashed approximately at 150F degrees for 60 minutes. Took 30 minute and 60 minute samples. Cooled both samples quickly. Tried to take at room temperature, but...

- 30 minute reading: 5.91pH @ 20.2c (68.36F)

- 60 minute reading: 5.74pH @ 19.1c (66.38F)

Second Test: 40g of Briess Rye Malt with 100 ml of distilled water mashed approximately at 122F degrees for 60 minutes. Took 30 minute and 60 minute samples. Added 200mg sodium bicarbonate after 30 minute sample was taken. Cooled both samples quickly. Tried to take at room temperature, but...

- 30 minute reading: 5.97pH @ 26.1c (78.98F)

Added 200mg of sodium bicarbonate after taking 30 minute sample.

- 60 minute reading: 7.16pH @ 23.1c (73.88F)

Hopefully, the above data will be of some help.

 

[Silver_Is_Money]

Thank you! Very helpful!!!

To me the Briess Rye Malt has a DI_pH of 5.74. I'm not sure what A.J. will consider the DI_pH to be. I'm shocked however that with zero acid or minerals in the water the pH would dramatically fall from the 30 minute mark to the 60 minute mark of the mash. I would have thought the reverse would happen. I wonder if 2-Row barley base malts perform similarly.

What was your method of maintaining temperature. A water bath? A heat plate? Both?

 

[ajdelange]

First Test: 50g of Briess Rye Malt with 100 ml of distilled water mashed approximately at 150F degrees for 60 minutes. Took 30 minute and 60 minute samples. Cooled both samples quickly. Tried to take at room temperature, but...

- 30 minute reading: 5.91pH @ 20.2c (68.36F)

- 60 minute reading: 5.74pH @ 19.1c (66.38F)

I can't say that this is impossible but for the pH of a mash (even a minimash) to change as much as 0.17 after a half hour would be very unlikely. Usually mash pH is pretty settled after 10 or 15 minutes and almost completely settled after 25 - 30. Were I to encounter what you saw the first thing I would do (after rinsing with DI water and blotting) is put the electrode back into the pH 4 buffer. When I see a pH reading that does not make sense I first and always suspect my pH reading and it nearly always turns out that this was what was responsible. That does not mean that is the case here. The pH might have indeed dropped that much. I've just never seen it and can't explain it.

Now you are using a new pH meter so it should be OK but on even a new meter you should do the stability test described in the Sticky on pH meters. A possible explanation is that you are a new user of pH meters. Is that the case? It turns out that new users of any measurement/assay technology get wild answers at first. I know I certainly did and not just with pH meters. Measurement is an art and it takes some time to acquire it.

Another thought here is the grind. In these experiments the malt should be ground to a fine flour with a spice grinder (as most of us don't have laboratory mills). Were the grind quite coarse it might take an hour for the water to reach the starch granules, burst them and hydrate the innards. How did you grind this grain? Also how about stirring?

Second Test: 40g of Briess Rye Malt with 100 ml of distilled water mashed approximately at 122F degrees for 60 minutes. Took 30 minute and 60 minute samples.

- 30 minute reading: 5.97pH @ 26.1c (78.98F)

The reading under the same conditions (without baking soda) of 5.97 at the 30 minute mark should compare, when adjusted for temperature, with the first reading of 5.91
It is 0.06 higher than the first reading though the temperature is 5.9 °C higher. It should, thus, be 0.03 to 0.08 lower. Thus there is a discrepancy of 0.09 to 0.17 pH between these readings. The magnitude of this discrepancy is comparable to the discrepancy between the 30 and 60 minute readings. Thus I suspect the readings

Added 200mg of sodium bicarbonate after taking 30 minute sample.

- 60 minute reading: 7.16pH @ 23.1c (73.88F)

Apparently this got missed:

At the begining of a second, separate procedure.

Nevertheless lets assume that the DI mash pH is 5.97 and refer that to 20 °C (using the average glide of 0.0055 pH/°C) as 5.97 + 0.0055* 6.1 = 6.00. At 60 minutes with the added bicarbonate (even though added late that shouldn't make too much difference) the pH, referred to 20 °C, would be 7.16 +3.1*0.0055 = 7.177. Thus the pH change was 7.177 - 6.00 = 1.177. With respect to pH 7.177 the alkalinity of sodium bicarbonate is 1.631 mEq/g. The buffering of this malt, as derived from these data, is thus -0.2*1.631/0.04/1.177 =-6.92863 mEq/kg•pH. That's pretty low. Again I can't say that the malt's buffering isn't that low but rather that I have never seen a buffering that low (or even close to that low). But then we have the discrepancies in the pH readings.

A good lab rat wants to see his data close on itself as I like to say. These data don't. When that's the case he tries to find out why and may wind up repeating the experiment several times until it does. You are probably not a good lab rat yet. Getting to be one requires experience (ever noticed that the oppositely charged rods on the floor of a Skinner box are spaced exactly the same as the separation of a male rat's.... oh, well , never mind).

Thank you! Very helpful!!!

To me the Briess Rye Malt has a DI_pH of 5.74. I'm not sure what A.J. will consider the DI_pH to be.

A.J would only conclude that the DI mash pH of this malt is high but would not draw a firm conclusion from these data. But he would join in extending thanks to Code and hope that Code feels that he profited from the experience and learned something.

 

[CodeSection]

Thank you! Very helpful!!!

What was your method of maintaining temperature. A water bath? A heat plate? Both?

Well, maybe not as helpful as it should be. I used a water bath to maintain the temperature.

...When I see a pH reading that does not make sense I first and always suspect my pH reading and it nearly always turns out that this was what was responsible...

Now you are using a new pH meter so it should be OK but on even a new meter you should do the stability test described in the Sticky on pH meters. A possible explanation is that you are a new user of pH meters. Is that the case? ...

Another thought here is the grind. In these experiments the malt should be ground to a fine flour with a spice grinder (as most of us don't have laboratory mills). Were the grind quite coarse it might take an hour for the water to reach the starch granules, burst them and hydrate the innards. How did you grind this grain? Also how about stirring...

Yes, I am a new user of the pH meter and it is a new unit. I did read the sticky on pH meters. I recalibrated it prior to use last night. I have not performed a stability test but will do so.

I used my MM3-Pro to grind. It was set for a very coarse grind of .045. I performed a double grind. I have it calibrated to two other settings (.035 and .040). It sounds like you would suggest even finer, correct?

I guess I missed the part of adding sodium bicarbonate before the second test. I thought it was to be added in the second test after the 30 minute reading.

I will perform the tests again. Let me know if the grind of .035 is sufficient. If not, I can see how difficult it may be to remove the hopper on the mill to allow me to adjust the rollers to give me a finer grind. I will perform stability tests on the pH meter as well.

Thanks.

 

[CodeSection]

@ajdelange , would a pepper grinder work? Btw, the mash was constantly stirred.

 

[ajdelange]

Do you have a coffee mill, blender...? The finer you can get it the less we have to worry about mechanical delays.

As you are new to pH measurement I would advise taking as many pH measurements of things around the house as possible as frequently as possible in order to pick up that art I refer to here from time to time. Orange juice, tomato juice, lime juice, vinegar, milk, ketchup your tap water, beer (degass it first)... Make multiple measurements of the same thing. Those measurements should be close to one another. If they aren't it is meter drift or your technique (and sometimes the sample itself changing e.g. warming or cooling, soda losing CO2). Confirm it isn't meter drift by the stability test.

 

[ajdelange]

@ajdelange , would a pepper grinder work?

Yes.

Btw, the mash was constantly stirred.

Good!

 

[CodeSection]

@ajdelange , could you please lay out the steps of when to add the sodium bicarbonate? When I reread what you wrote, it confuses me. I had added it after taking the 30 minute reading. Then stirred in and and took the 60 minute reading with the sodium bicarbonate for the second 60 minute sample.

When I wrote...
CodeSection said: ↑
Added 200mg of sodium bicarbonate after taking 30 minute sample.

- 60 minute reading: 7.16pH @ 23.1c (73.88F)

You wrote...
Apparently this got missed.

So, when do you want me to add it? Should I add it only to the original mash so the 60 minute sample shows the affect of the sodium bicarbonate, correct? I do NOT add it to the 30 minute sample, correct?

Thanks.

 

[Silver_Is_Money]

..... Nevertheless lets assume that the DI mash pH is 5.97 and refer that to 20 °C (using the average glide of 0.0055 pH/°C) as 5.97 + 0.0055* 6.1 = 6.00. At 60 minutes with the added bicarbonate (even though added late that shouldn't make too much difference) the pH, referred to 20 °C, would be 7.16 +3.1*0.0055 = 7.177. Thus the pH change was 7.177 - 6.00 = 1.177. With respect to pH 7.177 the alkalinity of sodium bicarbonate is 1.631 mEq/g. The buffering of this malt, as derived from these data, is thus -0.2*1.631/0.04/1.177 =-6.92863 mEq/kg•pH. That's pretty low. Again I can't say that the malt's buffering isn't that low but rather that I have never seen a buffering that low (or even close to that low). But then we have the discrepancies in the pH readings.

A.J., if instead the DI_pH was taken to be 5.74 (as for the 60 minute mash pH witnessed by @CodeSection), what would the buffering indicate for that specific case, and would it be more believable than the 6.92863 mEq/kg•pH you derived from DI_pH 5.97?

 

[ajdelange]

We are trying to see how a malt responds when placed in a mash with other malts and, quite possibly acids and bases. To do that we first measure the pH of the malt without any acid or base addition. Most of us agree that the pH measurement should be stable at 30 minutes but silver hypothesizes that it increases as time advances beyond that point. Thus we ask you to take two measurements, one at 30 minutes and one at 60. It is instructive to take as many measurements as you can. When I so it I leave the electrode in the mash at elevated temperature and take a reading every 15 sec. Doing this is supposed to be stressful to the electrode but actually is not. The stress occurs when you stick a cold electrode into hot mash and again when you pull it out and squirt it with cold water from the mash bottle. Nonetheless we are not asking that you leave it in the mash but rather withdraw small samples and cool them. Were you to leave the electrode in the mash you would see a sharp change in pH in the first five minutes and then a gradual settling to a quasi stable pH at about 30 minutes and then perhaps a gradual increase or decrease (in the same direction as the earlier trend) beyond 30 minutes. A change of more than this indicates a probable electrode instability problem. Now here's another thought as to why you might have seen the abrupt change. New electrodes can be finicky for a day or two after being pressed into service. Letting yours soak in its recommended storage solution may solve your problem (if indeed there was one).

Thus the procedure for minimash A is:
1)Place 40 mg finely ground malt in a beaker
2)Place the beaker in a water bath to warm the malt/beaker
3)Add 100 mL pre warmed DI water. Stir
4)Continue stirring frequently (needn't be continuous)
5)Withdraw sample for pH measurement as often as possible but be sure to get readings at 30 min and 60 min.

Now we come to the second sample in which we want to see how acid or base changes the pH of the test malt. This malt apparently has a high DI pH so we would prefer to add acid but as we don't, probably, have an acid of calibrated strength handy, add what is pretty close to a calibrated base and make the perfectly reasonable assumption that the titration curve we seek to get a second point from (the first point is the DI pH) is smooth and near linear in the region of the DI pH.

The procedure for minimash B is the same as for minimash A with a single exception in step three

1)Place 40 mg finely ground malt in a beaker
2)Place the beaker in a water bath to warm the malt/beaker
3)Add 100 mL pre warmed DI water into which 200 mg of NaHCO3 has been dissolved. Stir.
4)Continue stirring frequently (needn't be continuous)
5)Withdraw sample for pH measurement as often as possible but be sure to get readings at 30 min and 60 min.

Perhaps you were confused as to the time of addition of the bicarb based on familiarity with the way in which titrations are usually performed. In a normal titration a pH is measured, titrant is added, the new pH recorded, more titrant is added, the pH recorded again etc. We can't do that here because it takes half an hour for the reactions that change the pH to complete. In the normal titration we assume that the reactions are complete within seconds. Note that this is not always the case and can result in misleading data just as it would here. This, BTW, casts some doubt on Kai Troester's pioneering work as I believe he used conventional titration methods. But I use his data all the time.

 

[ajdelange]

A.J., if instead the DI_pH was taken to be 5.74 (as for the 60 minute mash pH witnessed by @CodeSection), what would the buffering indicate for that specific case, and would it be more believable than the 6.92863 mEq/kg•pH you derived from DI_pH 5.97?

It's quite clear from No. 137 how to recalculate the buffering under the assumption of a different mash pH. Why don't you give it a try in the hopes that the exercise will help you to understand what buffering actually is? It should be clear that if the DI mash pH is lower than I assumed then the bicarbonate moved the pH more so that the buffering, which represents resistance to pH change, will be less.

 

[Silver_Is_Money]

If the calculated buffering value is much lower than you anticipated, is the real suspect or culprit here the measured 7.16 pH after the 200 mg baking soda addition? Should the post baking soda pH have been measured to be noticeably lower than 7.16 in order to calculate as a consequence a higher resistance to pH change, or in other words, a greater buffering value?

 

[ajdelange]

Buffering equals magnitude of proton absorption or release divided by the pH change it causes. Thus the larger the pH change caused by a given sized base addition the lower the buffering. I had calculated the 0.2 grams bicarbonate against 40 grams of malt based on a desired pH shift of 0.1 pH. Indeed for Crisp's Maris Otter the pH shift would be expected to be 0.11 pH.

 

[ajdelange]

I guess I didn't really answer as to what I think is responsible for the buffering estimate that is apparently much too small. In cases like this one needs to look at all his data and an experienced lab rat will make sure there is data to compare for just this reason. Here the pH measurements are not consistent among themselves. They change over time when experiences tells us they don't do that and they go down when they should go down. Thus we conclude that the problem is that we don't have good pH measurements and can't really expect a good buffering estimate. A new man with a new meter supports the notion that the pH readings may be bad as it takes some time to gain the art and for the new electrode to settle in.

 

[CodeSection]

@Silver_Is_Money , @ajdelange , @ScrewyBrewer , well I thought I would post my results before proceeding to the second test. I used a pepper grinder to get a very fine malt. Please let me know about the results. If you believe the readings are way off, then I see no reason to continue with the second test with the addition of 200mg of sodium bicarbonate.

First Test: 40g of Briess Rye Malt with 100 ml of distilled water mashed approximately at 122F (50c) degrees for 60 minutes. Continued to stir throughout the 60 minutes. Recalibrated Milwaukee pH meter. Took 30 minute and 60 minute samples. Cooled both samples quickly. Tried to take at room temperature, but...

- 30 minute reading: 5.90pH @ 22.9c (73.22F)

- 60 minute reading: 5.83pH @ 19.6c (67.28F)

I waited for another hour after the 60 minute reading to take readings again from the samples.

- 30 minute sample: 5.91pH @ 22.1c (71.78F)

- 60 minute sample: 5.83pH @ 20.6c (69.08F)

I still have the samples and can take another set of readings....

How would you like to proceed?

 

[Silver_Is_Money]

Thanks!!! I'm happy with this. A.J. will want 0.2 grams (200 mg.) of baking soda mixed in well, followed by a rest, and another round of pH readings.

On my next update of Mash Made Easy I will include Rye Malt at a DI_pH of 5.90, by adding it in along side of wheat malt (white or red, which in MME is also presumed to average 5.90 DI_pH).

Interesting that D.M. Riffe has data which shows flaked rye at 6.65 DI_pH, whereas regular malted rye is closer to 5.9. But the same holds true for flaked wheat vs. malted wheat as well. The light kilning of malted grains must be the difference here. And that seems to be fully in line with additional kilning (to bring out more Lovibond darkness) inducing even more acidity.

 

[ScrewyBrewer]

@CodeSection thank you for your effort and for sharing your results here. As @SilverIsMoney points out the 5.90 DipH seems like a reasonable starting point for the Briess Rye malt. @ajdelange I'm sure would prefer to have at least one additional titration point to confirm the malt's buffering. But we are off to a great start now.

 

[ajdelange]

The picture that is emerging is that of a malt with 30 min DI mash pH of 5.90 and 60 min mash pH of 5.83. IOW, it appears that this malt doesn't fully react with water in 1/2 hour. It also appears that the reaction stops (or slows way down) when the sample is cooled. The fact that the measurements are now more closely grouped and apparently stable over an hour (when cold) lends increased confidence to this measurement set.

Now would I like to see some measurements at other than DI pH? Absolutely! Now let me start off by saying that in my previous posts on the bicarbonate addition I must have slipped a decimal point. 200 mg of bicarbonate would shift 40 grams of an average malt by almost 1 pH. We are looking for less than that. Say 0.1 pH. Thus I should have been recommending 20 mg, not 200! So let's change the recommended size of the addition to 40 mg. That should cause a pH rise of 0.2 if the malt's buffering is -40. Now that may be hard to measure out with the scale you have available in which case I would recommend dissolving a gram in a liter of DI water (or half a gram in half a liter or whatever is convenient) and then measuring out 40 mL of that to which add straight DI water to make up the 100 mL for the mini mash.

I don't know how far you are interested in going here and certainly several people, including me, are already grateful for the effort you have put into this. If you are interested in continuing these experiments I'd suggest going in the other direction i.e. adding acid rather than base. If we get buffering information based on adding bicarbonate that's clearly better than the information we have now (none) but how will be use it? We will have to project it backwards to mash pH to find out how much acid we would need to add to a given amount of this malt to realize a good mash pH. This assumes that this malt is linear, which it isn't and involves what one author called "bold extrapolation" which scientists and engineers hate to do (I saw Karl Siebert ream out some poor guy who barely spoke English at an ASBC meeting for doing it). Thus it would be much better if we could do our tests with an acid rather than baking soda. At this point I think citric acid might be the best candidate because it is readily available but let's defer discussion of that until after you get a bicarbonate reading and decide whether you wish to go further.

 

[ScrewyBrewer]

So when using 'Bicarbonate' we mash 40 grams of finely crushed grains in 100ml of RO water at 122F then taking measurements at 30, 60, 90 and 120 minutes.

Then repeating the process but this time adding 40ml of a bicarbonate solution made from 1 liter of RO water and 1 gram of Baking Soda. Correct?

Also under consideration I think for use in acid titration is 1N (1 normal) hydrochloric or sulfuric acid. Or making a dilute Lactic acid solution from 1 cc of 88% lactic acid added to 100 mL of DI or RO water. Although AJ has made a case for not using Lactic acid but I don't remember what is was.

 

[CodeSection]

I have an AWSPro-200 (200x0.01g) scale, and it will measure 0.04g. I will start the second test soon....

 

[ScrewyBrewer]

I have an AWSPro-200 (200x0.01g) scale, and it will measure 0.04g. I will start the second test soon....

That scale's a lot more accurate than my 1.0g accuracy model. But I think you'll need 40g not 0.04g.

 

[CodeSection]

....Now let me start off by saying that in my previous posts on the bicarbonate addition I must have slipped a decimal point. 200 mg of bicarbonate would shift 40 grams of an average malt by almost 1 pH. We are looking for less than that. Say 0.1 pH. Thus I should have been recommending 20 mg, not 200! So let's change the recommended size of the addition to 40 mg. That should cause a pH rise of 0.2 if the malt's buffering is -40. Now that may be hard to measure out with the scale you have available in which case I would recommend dissolving a gram in a liter of DI water (or half a gram in half a liter or whatever is convenient) and then measuring out 40 mL of that to which add straight DI water to make up the 100 mL for the mini mash....

That scale's a lot more accurate than my 1.0g accuracy model. But I think you'll need 40g not 0.04g.

Use 40mg (0.04g), correct?

 

[Silver_Is_Money]

Yes!

40 mg = 0.040 grams

 

[CodeSection]

@Silver_Is_Money , @ajdelange , @ScrewyBrewer , here are the results of the second test with the addition of 40mg (0.04g) of sodium bicarbonate.

Second Test: 40g of Briess Rye Malt with 100 ml of distilled water with 40mg (.04g) of sodium bicarbonate added to water prior to mash. Mashed approximately at 122F (50c) degrees for 60 minutes. Continued to stir throughout the 60 minutes. Took 30 minute and 60 minute samples. Cooled both samples quickly. Tried to take at room temperature, but...

- 30 minute reading: 6.10pH @ 22.4c (72.32F)

- 60 minute reading: 6.04pH @ 22.5c (72.50F)

I waited for another hour after the 60 minute reading to take readings again from the samples.

- 30 minute sample: 6.11pH @ 21.8c (71.24F)

- 60 minute sample: 6.05pH @ 21.8c (71.24F)

I hope this helps...

 

[ScrewyBrewer]

Use 40mg (0.04g), correct?

I was referring to the 40g grain and 100ml RO water mash for the DIpH testing. Just to be clear.

“So when using 'Bicarbonate' we mash 40 grams of finely crushed grains in 100ml of RO water at 122F then taking measurements at 30, 60, 90 and 120 minutes.

Then repeating the process but this time adding 40ml of a bicarbonate solution made from 1 liter of RO water and 1 gram of Baking Soda. Correct?”

 

[ScrewyBrewer]

So the readings are....

5.90 pH no bicarbonate
6.10 pH with .04g bicarbonate

...a .20 pH increase..