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Low pH, cause for concern?

I brewed a outmeal stout last week and a cream ale this week. Both times I did batch sparging. the pH after the mash was 5.2ish on both brews. I did a mash out and did the lautering of the first runnings. Then I proceeded to add my sparge water and stirred and after a few minutes took another pH test(using strips). The pH was slightly lower than 5.0. I typically have never tested pH for the second batch and my beers always, IMO, come out fine. Should I be concerned with a slightly lower than average pH? Should I add something to bump it up?

I wouldn’t do any thing to it it should be fine. I’ve had the ph below 5 a couple times with no issues.

Someone with more chemistry knowledge could maybe echo or reverse my thoughts here, but I don’t think its physically possible for you to have had 5.0 PH. I am leaning towards the second test parameters or strip being suspect first. I would think any water has to be base PH or higher depending on mineral content and that would tend to always see a rise in the mash PH during lauter.

Unless you acidified your sparge water to 5.0 or under I am leaning towards your sparge starting at 5.2 and never saw a rise above 6.0 maybe?

I used this:

http://www.northernbrewer.com/shop/medi ... e_1890.jpg

My first batch was pretty much on: 5.2
my second runnings matched the yellow on the chart indicating 5.0

Well, That may indeed be the problem. Not saying definite as some folks can have success using those inexpensive types of strips. I used them initially myself when starting brewing and they were worthless, no matter what I got a reading indicating 5.0 PH or under and I knew that was Cr0p. I got a PH meter right away and it showed I was actually mashing around 5.6 and higher and then I got hip to water chemistry and solved my mash and sparge PH as I fly sparge.

As a second frame of reference I happened to see my old strips just like what you have in my brewing “toolbox” one of my last batches and happened to test a known sample. What do know WAY off. The true reading was 5.5 PH and I showed good ole 5.0 PH range again.

One other thing with any strip is the light source you view it in can also can be a factor of color showing.

On this same train of thought the ColorpHast strips that are slightly higher in cost have a known deviation that can be relied upon. A couple of brewers including BrauKaiser have found the exact PH deviation the better strips have and now we can rely on a tighter reading, whereas the “cheaper” strips are all over the place. Also a good tactic that board member Denny mentioned years ago was to cut the nicer strips in half doubling your strips. Here is Kai’s page about the better strips:

http://braukaiser.com/wiki/index.php?ti ... me_brewing

Now to continue this thought if you lean towards a PH meter in the future Kai has a page giving a good summary also:

http://braukaiser.com/wiki/index.php?ti ... s_pH_meter

NB has the better strips but last I looked they were pretty spendy and you can find them for cheaper elsewhere. But in that same line of thought NB has a fair price on the new Milwaukee PH meter that has really tight numbers in its testing parameters.
IE: you can measure down to the 0.01 -/+ whereas in the past brewers price range meters measured around -/+ 0.10-0.20 PH. The Hanna Instruments Co makes a newer similar model also.
This is the Milwaukee PH 56:

http://www.northernbrewer.com/shop/milw ... rtini.html

The PH 55 is cheaper but it only reads -/+ 0.10 which is still fine it depends how much accuracy you need.

Bottom line this go around is I still have to think you mashed in around 5.2 or higher and your lauter either stayed close to original PH or rose slightly to under 6.0 depending on your exact water composition. Again I’m not the super chemist here so if anybody would echo or reverse my thoughts here I would welcome that input.

The only reason you would be 5.0 PH or under “Maybe” would be if you had super large amounts of roasted grain or other that would naturally cause a dip that low. Or you had amounts of sauermalt or real-real slack/ moist grain** in the grist. Even then I have seen discussion stating that under normal mashing situations it is real hard to mash under 5.0 as a bottom. So if you did hit 5 your cast out and/ or post ferment should still be no lower than 4.5 which is totally within parameter “I think” I cannot recall the exact range of working post ferment PH numbers you should see. Kai does observe either his cast out wort and/or post ferment PH and adjusts, so you may find reference in his site about this topic also if you wish.

** In extreme circumstances brewers find that stored grain that was or has become slack or moist can grow molds or bacteria that would naturally lower the PH. Again this is a super rare condition in your average malt though and would happen 1 in 10,000 times as most malt is well cared for in today’s LHBS and supply chains.

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