Low mash pH from rainwater

[mtb]

I posted a status about this earlier but there is some debate regarding the source of my "astringency" so time to start a thread.

I brewed a few batches with rainwater, thinking at the time it was town water coming from my tap. Because I thought it was town water I added acids & minerals accordingly to bring it in line with my target water profile. The beer - and subsequent batches brewed on the same day - had the same dry, puckering, teabag taste that seem to go hand-in-hand with astringency. I want to emphasize here that I brewed two separate batches with different ingredients, yeast and hops. They were brewed on the same day with different water.

My town water is 7.7pH, rainwater averages around 5.5pH according to Google with some variation in local pollutants etc, so by adjusting rainwater with minerals & acids believing it was town water, I essentially reduced the pH of rainwater (ph ~5.5) to a much lower level because I believed it was 7.7. I can only assume the mash pH of the brews were below 5, or close to.

Thoughts on the above? Does this sound correct? Low mash pH isn't well covered in online articles but I can only assume it's as problematic as a high pH.

 

[husky]

What are you using to lower the pH? I notice that calculators tell me to add 2ml lactic acid to drop my mash pH into the 5.4-5.6 range however actual results mean I'm only actually adding 0.5ml as 2ml drops it into the 4's. I'm assuming you don't have a pH meter so its possible if you're using acid and the water calculators recommended dose you could be way low on pH. My reading indicates the pH should be above 5 and ideally between 5.4 - 5.6.

 

[manticle]

Have you measured actual mash pH?

Have you measured rainwater pH and mineral concentration?

 

[Danscraftbeer]

I don't think you should worry. My filtered Melbourne water is 5.5 and after I add minerals its still 5.5 read by a calibrated AD11.
I still add Acidulated malt (edit: ~ 1.5 - 2%) to get a mash pH of 5.2 - 5.4. I like this fact that my neutral waterwater to begin with is close to the mash pH.
Rather than more dramatic swinging pH readings.

 

[dent]

Rainwater alone won't result in a low pH for brewing purposes - even with distilled water the pH is still too high (5.8 with pils malt).

Measuring the pH of the water is a waste of time. Check your mash pH instead.

It is likely you've overdone the mineral additions which has resulted in the perception of astringency in your beer. CaSO4 in particular will have this effect.

If you're feeling conservative, next time do no mineral or acid additions whatsoever to the rainwater. The pH will not be awesome, nor will be your efficiency, but your beer will most likely be fine and it would be a useful test to eliminate any other variables.

 

[Lyrebird_Cycles]

I essentially reduced the pH of rainwater (ph ~5.5) to a much lower level because I believed it was 7.7. I can only assume the mash pH of the brews were below 5, or close to.

Thoughts on the above? Does this sound correct?

Very unlikely on Canberra water. According to Icon water the mean alkalinity of Canberra water is 37 mg/l which means you need 0.033 g/l lactic acid (ie slightly under 1 ml in a 30 litre brew) to correct it back. The buffering capacity of rain water is 3/10 of FA.

In my experience if you are going to get astringency from water pH the first suspect would be high pH in the sparge water, this tends to pull more phenolics from the husks (phenolics are more soluble in hot, high pH water)

 

[Jack of all biers]

Agree with the above two posts entirely. Forget what the pH of the water is, but concentrate on the residual alkalinity (buffering capacity). Using calculators as a guide is fine, but if you are going to take the calculated results seriously, then you need to get serious and measure your pH even if it is with pH strips.

*pH of strike water (liquor) is not important unless it is extremely high or low (talking outside the range pH 4.5 - 9) and then there would be other problems such as high mineral-metal content that has other more significant problems than mash pH values (talking health consequences).

My town water is 7.7pH, rainwater averages around 5.5pH according to Google with some variation in local pollutants etc, so by adjusting rainwater with minerals & acids believing it was town water, I essentially reduced the pH of rainwater (ph ~5.5) to a much lower level because I believed it was 7.7. I can only assume the mash pH of the brews were below 5, or close to.

Thoughts on the above? Does this sound correct? Low mash pH isn't well covered in online articles but I can only assume it's as problematic as a high pH.

This is the problem with Googling for a solution. Yes whilst pH of rainwater is around 5.5, that is whilst it is falling from the sky. As soon as it hits your dusty/leafy roof it changes. Runs into your dirty gutters, more change. Lands in your tank (plastic, galv, concrete or otherwise), more changes. Sits there for some months/years with rotting vegetable matter, more changes. It is constantly in flux due to the environment it is in. For instance, my rain water sits in a large galv tank and was last measured a few weeks ago, with a resulting pH of 6.2. I have no doubt that the buffering capacity or residual alkalinaty of that same rain water would be sweet FA and not much of a bees appendage different if it was pH 5.5 or 7.2.

On a side note, I was at Wiesbaden, Germany a few weeks ago and they have hot springs in the centre of town, which people drink for the health benefits (It comes out of the ground ~50C). I took the attached photos of the mineral profiles, but they recommend that people drink no more than 1 litre of this stuff in any one day and not to drink it over a lengthy period. Not sure the pH value though, but the mineral content is nuts (why did I immediately think of the difficulties of brewing a beer with this water h34r. Note the Arsenic Content is 9 times over the recommended drinking water limit (Manganese also slightly over, but not such a problem).

 

[mtb]

Sounds like I need to brief SWMBO on the benefits of a pH meter.. I'll measure mash pH properly - can't just rely on what I believe is my water source, and the predicted pH of such. I was reducing my water pH with citric acid (no lactic acid on hand) but I could probably avoid lots of trouble by simply sourcing my water from the house rather than my man-cave tap.
LC, I was never too concerned with my water pH (Canberra water is about on point as you referenced), but I thought I'd experiment. Unfortunately, that experiment relied on assumed variables that changed over time/weather.. nothing worse than watching 40L of Blonde Ale gurgle down the drain. I might just brew with water direct from the kitchen tap as I know it is town water, as opposed to the outside tap.

LC - I didn't sparge with these brews, mostly to avoid the issues you listed, thankfully I can rule that out.

I assumed that by adding 4g of citric acid to 38L of strike water, assuming the water was 7.7pH, I was reducing it to levels that wouldn't support a good mash.. but maybe there were other variables at play. I'll need to try again. Did somebody say New Beers Eve Ale h34r:

 

[Jaded and Bitter]

mtb buy a good pH meter rather than guessing. like a milwaukee mw102 etc. order from amazon or online in US for best price.

 

[Kono]

Agree with the above two posts entirely. Forget what the pH of the water is, but concentrate on the residual alkalinity (buffering capacity). Using calculators as a guide is fine, but if you are going to take the calculated results seriously, then you need to get serious and measure your pH even if it is with pH strips.

*pH of strike water (liquor) is not important unless it is extremely high or low (talking outside the range pH 4.5 - 9) and then there would be other problems such as high mineral-metal content that has other more significant problems than mash pH values (talking health consequences).


This is the problem with Googling for a solution. Yes whilst pH of rainwater is around 5.5, that is whilst it is falling from the sky. As soon as it hits your dusty/leafy roof it changes. Runs into your dirty gutters, more change. Lands in your tank (plastic, galv, concrete or otherwise), more changes. Sits there for some months/years with rotting vegetable matter, more changes. It is constantly in flux due to the environment it is in. For instance, my rain water sits in a large galv tank and was last measured a few weeks ago, with a resulting pH of 6.2. I have no doubt that the buffering capacity or residual alkalinaty of that same rain water would be sweet FA and not much of a bees appendage different if it was pH 5.5 or 7.2.

On a side note, I was at Wiesbaden, Germany a few weeks ago and they have hot springs in the centre of town, which people drink for the health benefits (It comes out of the ground ~50C). I took the attached photos of the mineral profiles, but they recommend that people drink no more than 1 litre of this stuff in any one day and not to drink it over a lengthy period. Not sure the pH value though, but the mineral content is nuts (why did I immediately think of the difficulties of brewing a beer with this water h34r. Note the Arsenic Content is 9 times over the recommended drinking water limit (Manganese also slightly over, but not such a problem).

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DSC_2047.JPG

Looks like its mostly just salt water (Natrium is Sodium) and a high CACO3 level as well but the rest looks fine. We have those trace minerals in our water as well, the main thing that would be benefiting health would be the alkalinity and sodium (too many people dont get enough salt these days). That would also be why they shouldnt drink more than 1L per day, too much Sodium! look at the TDS! HUGE!