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Ph, Tannins, Ferulic Acid?

Post #1 made 13 years ago
by deebo
Just wondering if anyone here can explain to me the effects of high (I think this is the right term?) ph?
I took a couple of readings with a cheapo ph meter and some strips on my last brew, results as follows:

filtered water for brew 7.8 ph
6.0 ph at start of mash
5.8 after draining bag,
5.7ph at 38:55 left of boil (mixed grain and added a bit of heat)

From what I can tell this is too high (or low.. I never learned the ph scale properly).

First Question:
I noticed on http://braukaiser.com/wiki/index.php?ti ... ts_brewing they have ferulic acid release listed at this ph but at a lower temperature.. I have noticed a bit or sourness in my last couple of beers (one was a witbier so wasnt too bothered by it, but it is not so great in a porter) and was wondering if this could be the cause (could just be a mild infection also I guess). Was also thinking I may be confusing the taste as sour when it is tannins.. as they mention high ph can also extract more of these?

Second Question:
What should I add to my water to correct the high (or perhaps low) ph? (water report below)
I do have a bunch of calcium sulphate handy that I added a small ammount of to a few brews but didnt really notice any change.
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Post #2 made 13 years ago
by BrickBrewHaus
A few questions...

1) Are you calibrating the pH meter?
2) When taking pH measurements, are you cooling the wort sample to room temp?
3) What was the grain bill of the beer you measured these pH values for? The witbier or porter or something else?

Your water isn't too bad. The alkalinity is a little high, but certainly within the range of acceptable. This is balanced pretty nicely with calcium and magnesium. With any kind of dark kilned malts (your porter), the pH should fall nicely into place. For lighter beers (your witbier) you may want to consider adding a little lactic acid, calcium chloride, or gypsum to pull the pH down a bit. According to braukeiser, a mash pH of 5.8-6.0 is considered the threshold for tannin extraction, above this you're getting excessive tannin extraction. I wouldn't consider your pH of 5.8 above this threshold (unless your meter isn't calibrated or you're taking the reading at mash temperature).

But all-in-all, your water is pretty good.

Now, regarding the ferulic acid...Are you mashing in at a low temp (around 110F, 40-45C)? If not, then ferulic acid is not being released. Ferulic acid release seems to be an enzyme by-product, which is very sensitive to pH AND temperature. You may be in the right pH range, but if you're not in the temperature range for this enzyme then you're not getting that effect.

My guess is that its a sanitation issue. Are there any processes in your brew day that you think are a little dodgy? Any plastic pieces that haven't been replaced in a while? Do you have a ball valve that isn't being cleaned thoroughly?

You can continue to look into the pH thing if it interests you, but your main concern should be on the sanitation (if, in fact, that is the problem).
Last edited by BrickBrewHaus on 10 Apr 2012, 20:58, edited 3 times in total.

Post #3 made 13 years ago
by deebo
1. I did calibrate it (with 2 solutions) and the test strips seemed to corroborate (i think thats a word.. or an indigenous dance) the results
(I dont suppose you know how long the test solutions last? I stuck them in the fridge in the hope I could use them again.)
2. I tried both, it didnt seem to change the reading a whole lot? (how much should the reading change with temperature?)
3. Was a witbier, about 41% wheat and 59% export pils

Am mashing in at mash temp (65c for the mash the readings were taken from)
Wasn't sure if 'some' ferulic acid would be released at higher temps if the ph is right or not (kinda like 'some' enzymes will work at higher or lower than optimum temperatures)

Should the reading I am basing any calculations on be taken at the start/midddle/end of the mash?

I starsan and clean the fermentation vessel and tube I use to transfer the wort to the fermenter. I have recently put down another witbier and an apa so if I get the same slight sour taste in them I will probably just buy a new fermenter to see if I can rule that out.

Seeing I have had a number of really good brews I think it may be sanitation.. (but not really sure why yet) but also was not sure if the ph may be contributing to some flavours given the values I got. No doubt I need a few more brews to try and see any kind of patterns with all the variables.

Would other acids like citric or malic acid be suitable for pulling the ph down? (I havent seen lactic acid available so might have to search for it)

Post #4 made 13 years ago
by BrickBrewHaus
deebo wrote:1. I did calibrate it (with 2 solutions) and the test strips seemed to corroborate (i think thats a word.. or an indigenous dance) the results
(I dont suppose you know how long the test solutions last? I stuck them in the fridge in the hope I could use them again.)
2. I tried both, it didnt seem to change the reading a whole lot? (how much should the reading change with temperature?)
3. Was a witbier, about 41% wheat and 59% export pils
1) OK, good. Its not the best practice to reuse the buffer solutions. As you add small amounts of other liquids (remaining on the end of the meter from previous measurements) you dilute the solution and slightly change the pH of the solution. If you're expecting it to be 7.01 or 4.01 pH, but its actually something like 6.9 or 4.1 you start to lose accuracy. Refrigeration shouldn't matter at all. They're just salt solutions.
2) What were the actual values at both temps? The most commonly cited value is 0.3 unit change from mash temps to room temp (mash temp giving the lower reading).
3) Your pH makes sense to me then. If you look at a recent experiment I posted here, you'll see similar pH readings for the 100% base malt. Your residual alkalinity is 72-104.[/quote]
deebo wrote:Should the reading I am basing any calculations on be taken at the start/midddle/end of the mash?
Take it at multiple times throughout the mash, starting with immediately after doughing in then every 10min after that. I've found that it stabilizes rather quickly, but I recommend finding out for yourself.
deebo wrote:Would other acids like citric or malic acid be suitable for pulling the ph down? (I havent seen lactic acid available so might have to search for it)
Sure, those would work too. When adding acid, be sure to add a little, stir, check pH. Add more if necessary.
Last edited by BrickBrewHaus on 10 Apr 2012, 22:34, edited 3 times in total.

Post #5 made 13 years ago
by joshua
Good Day, If your NOT making a very pale Ale/Lager, I have found 3oz/85g per 5gal/23L of Dark Roast/Black Barley will bring the Ph down from 7.0 to 5.6

It is not the perfect 5.2 but IS better than 7.3!

Just MHO.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #6 made 13 years ago
by PistolPatch
[Edit: Sorry deebo. Wrote this a few hours ago but forgot to hit 'Submit'. BBH will have much better answers than I but I'll click anyway ;)]

Hi there deebo,

I'm pretty ignorant about pH and water profiles. I've probably always lived in a 'lucky' area where the brews turn out well regardless.

What I do try and do but sometimes forget is adjust the pH down to around 5.2 to 5.3. I use acidulated malt to do this. I like thie idea of being chemical free and it only takes about 100 grams in a 40 litre mash to get things down form about where you are. (Never thought about it before but it is also a cheap way of adjusting pH.)

I've been that busy recently, I haven't done a brew for a while. Previously I had pH strips and was able to add about the same amount of acid malt to every brew (regardless of grain bill type) and always score 5.2 -5.3.

On my brews just past, I had run out of pH strips and couldn't buy them anywhere so ended up purchasing a pH meter. I added the same amount of acid malt as I did previously and found my brews were down around 4.7 so either my water has changed or I have a dodgy meter :lol:.

Anyway, I think acid malt is a nice way to go. Grind up a bit extra, put some in your grain bill and sprinkle more in at mash in until you get the right pH.

I used to use other stuff like citric acid but I much prefer the acid malt now.

:peace:
PP
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Post #7 made 13 years ago
by deebo
Thanks for all the help/info brewers. I think I might chuck in a bit of gypsum in the next few brews (assuming they are light in colour brews) and also take readings just to get more of a feel for it.

PistolPatch, I seem to remember reading in one of your posts a while ago that you had some ph 5.2 stabiliser but dont use it anymore, why did you stop using it (if it was your post :P) Might have to get some acid malt and give that a go also (does it add any sourness to the brew?).

Post #8 made 13 years ago
by PistolPatch
I did give the 5.2 a try and still have some left :).

Even given a full volume mash, I found it took more to get to 5.2 than stated. In other words, if you are going to use the stuff, I think you really need to have a pH meter or strips to know how much to use. It's also quite expensive.

And, if you have pH strips or a meter, then you might as well go acidulated malt. It's certainly more natural and cheaper. (I do use PBW and Starsan but the 5.2 is just not a practical product for me.)

:peace:
PP
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Post #9 made 13 years ago
by BrickBrewHaus
PistolPatch wrote:And, if you have pH strips or a meter, then you might as well go acidulated malt.
That's a very good point. Especially considering all of the negative comments I hear about it.
Last edited by BrickBrewHaus on 12 Apr 2012, 19:38, edited 3 times in total.

Post #10 made 13 years ago
by PistolPatch
Hey there BBH, what were the negative comments? I've never really read up on it.

And deebo, sorry, I forgot to answer the sourness question. I have never noticed a problem or heard of a problem even from one of the best lager brewers that lives here and put me onto it in the first place. So, I think there are no problems there.

Here's the link. A really good link at a glance but not helpful when you are trying to work out how much acid malt to use to get you in the ballpark.

I'll leave BBH to study it and draw any conclusions as he's fired up on this subject ans light years ahead of me in his understanding.

:peace:
PP
Last edited by PistolPatch on 12 Apr 2012, 20:21, edited 3 times in total.
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Post #11 made 13 years ago
by BrickBrewHaus
Short on time here, let me know if you want better explanations...

I've read a lot of comments about 5.2 that it doesn't really bring the pH to 5.2. That's the biggest thing (rightfully so since that what it claims to do). But I've never tried it, so take this with a grain of salt.

Regarding acid malt and the link you provided...They say 1% acid malt will reduce the mash pH by 0.1. But this is assuming that the acid malt was not part of the original grain bill. So lets say you dough in with 10kg of grain and a pH of 5.7. If you add 1% acid malt (0.1kg), the pH in theory should be 5.6.

BUT, this is also assuming a "normal" liquor to grain ratio. You won't find this written anywhere though, at least not in the same website that claims 0.1 pH unit drop for 1% acid malt addition. (Everyone assumes that everyone is using a "normal" mash.) The reason is the increased buffering capacity of more water (ie, higher l:g ratio as is used in BIAB). I can see how relying solely on acid malt or any other kind of acid can be prolematic because we would need more acid (due to higher buffering) to drop the pH an equivalent amount, for instance 3% acid malt for 0.1 pH drop.

So, getting completely off topic here...That's why I think water adjustment needs to be attacked on several fronts. If a persons water isn't suitable for brewing BIAB (I'm talking about too high of alkalinity), then just adding acid or just adding salts to reduce the pH is the wrong way to go. You'll need way more acid and even more salts to get the appropriate drop in pH, compared to the "normal" brewer using a "normal" l:g ratio. Rather, a better way, I think, is to dilute your water with distilled or RO water to reduce the alkalinity, then the acid or salt you add will have a greater pH-reducing affect.
Last edited by BrickBrewHaus on 12 Apr 2012, 20:58, edited 3 times in total.
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