Effects of Mash pH in Low/No Alcohol Brewing

Effects of Mash pH in Low and No Alcohol Brewing

As most brewers have read or been told, the pH of your mash matters a lot, some brewers are unsure why? And adjust their pH because it’s what everyone recommends, or what they’ve been told to do to make better beer. The reason pH matters so much is because there is an optimum pH range for enzymatic conversion of the starches extracted from the grains, a proper mash pH contributes to better flavour, improved conversion, and improved stability. The optimum range is between 5.2-5.6 pH and should be measured at room temperature with a correctly calibrated pH meter, if you measure the pH at mash temperatures, the higher temperature can cause a lower reading by 0.35, and what might be a perfect 5.4 pH at room temperature may be 5.05 pH at mash temperature and could quickly panic an unseasoned brewer.

Wandering outside of this optimum range is not a recommended practice and can cause many issues such as; inefficiency of conversion, off flavours, and reduced body and mouthfeel, it can also cause a less than ideal environment for yeast growth and overall health. Mashing too high >5.8 pH has been spoken to cause increased tannin extraction, increased malt colour compounds causing a darker beer (favouring dark beers), increased harshness, or astringency from increased hop acid solubility. Mashing too low <5.0 pH has been stated to reduce extraction of malt colour compounds (favouring light beers), increased protein coagulation and greater “hot break” (causing clearer wort), reduced hop acid solubility (less/softer bitterness and flavour), reduced alpha-amylase enzyme, cleaving of proteins making a thinner body and mouthfeel, and reducing foam positive properties.

While some brewers have noted very little difference in their finished beer, others have been able to distinguish slight changes. This may be fine for regular brewing, but what about brewing low/no alcohol beers? How does this change affect the finished beer? Considering low/no brewers are already pushing the traditional boundaries with mashing techniques, utilising greater mash temperatures, higher specialty grain and adjunct percentages, and lower bittering units. Another thing with low/no alcohol brewing is the pre-acidification of the wort prior to pitching the yeast to a food safe level of 4.6 or below… What if a brewer was to mash at our target pre-pitch pH around 4.6, rather than standard mash pH around 5.2-5.6? And what kind of beer are we making if we’re using un-adjusted scheme water mash?

We took this opportunity to investigate, and push for a greater understanding of brewing Low and No alc beers.

Mash pH Effects of Low/No alcohol Beer

With many brewers stating the important of mash pH, we put to test the effects of low and high mash pH in the making of low/no alc beer. With higher mash temperatures, higher specialty grain and adjunct percentages, and lower grain amounts, we investigate how much an impact mash pH affects the final beer. In this experiment we will be brewing a simple Aussie style Lager, a style that doesn’t have much room to hide any flaws, and any increased differences should become quite discernible. We will brew three batches exactly the same side by side, with the only variable being the pH of the wort during the mash. Keeping the water mineral adjustments as similar as possible, one batch will be lowered using Lactic acid to a pH of 4.7 (approx. pre-pitch acidification level), then next will be adjusted to 5.2 (standard mash pH), and the last raised to 6.4pH (approx. un-altered scheme water pH). I’ve also omitted any fining/clarity agents to the hot side to get a sense of how the pH affects turbidity, colour, and flavour.

BATCH SIZE	MASH TIME	BOIL TIME	IBU	EBC	EST. OG	EST. FG	ABV
12.0L	30 mins	30 mins	19.0	11.2 EBC	1.006	1.004	0.3 %
FV Volume				Actuals	1.008	1.004	0.5 %

Taste Maker Lager

Grain Bill

NAME	AMOUNT	%
Maris Otter (Simpsons)	228g	31.2
Munich, Light (Joe White Maltings)	204g	27.9
Carapils (Weyermann)	102g	13.9
Crystal, Light (Simpsons)	102g	13.9
Flaked Barley (Blue Lake Malting)	96g	13.1

Hop Schedule

NAME	AMOUNT	TIME	USE	FORM	ALPHA %
Super Pride (Aus.)	3.5 g	30 min	Boil	Pellet	13.3
Saaz (Czech)	20.0 g	5 min	Boil	Pellet	14.5

Yeast

NAME	LAB	ATTENUATION	TEMPERATURE
M54 California Lager	Mangrove Jack	33% (Est.)	19°C – 20°C

Base Mash Water Profile

Water Profile: Ca²⁺52 | Mg²⁺ 2 | Na⁺ 17 | Cl⁻ 57 | SO₄²⁻ 78 | HCO₃⁻ 16

To start off with, we collect our mash water amounts for each batch, staggering each batch to allow for us to have a good flow we bring the water for our first batch up to our strike temperature of 82ºC (179ºF). Once we reach our strike temperature, our grain and our water adjustments are added to the kettle, receiving a small dose of 88% lactic acid to target our mash pH to 4.7. Once that gets going, we start on the second batch, bringing the water to the same strike temperature of 82ºC (179ºF), add our grain and water adjustments to the kettle for our middle pH beer of 5.2. We move to get the third under way. Once again bringing the water to the same strike temperature of 82ºC (179ºF), add our grain and water adjustments to the kettle and a small dose of baking soda (NaCHO3) to raise the target mash pH of ~6.4.

Left: Low pH Mash

Middle: Regular pH Mash

Right: High pH Mash

Aiming for a 30 minute mash cycle on each of the beers, we check each batch at the 10 minutes mark of mashing. We take a quick pH reading to ensure we are on target for each of pH levels, and each left to mash for a further 20 minutes each at 80-81ºC (176ºF).

Left: Low mash pH 4.7

Middle: Regular Mash pH 5.24

Right: High Mash pH 6.41

Once the first batch has completed its mash, we remove and squeeze the bag to drain the remaining wort, we then check our pre-boil gravity and proceed with the boil.

Left: Low pH mash 1.008 SG

Middle: Regular pH mash 1.008 SG

Right: High pH mash 1.008 SG

Once the wort of the first batch has reached a boil, we start the timer for 30 minutes and add our first hop additions, continuing our way through the hop schedule. Doing the same for the other two batches. Once the boils are complete, we take a sample to measure our post-boil gravities, which will be our starting gravity (SG) before transferring the hot worts to our HDPE cubes to cool down to pitching temperature, we also make our pre-pitch acidification adjustments to a pH 4.5.

Left: Low pH wort

Middle: Regular pH wort

Right: High pH wort

Once the worts have cooled down to our pitching temperature of 19ºC (66ºF), we pitch half a pack (5.0g) of Mangrove Jack M54 California Lager yeast into each cube and are left to ferment in the fermentation chamber for 7 days. Once we have ensured we have reached our FG, we cold crash at 4ºC (39.2ºF) for 4 days, then transfer to the kegs for carbonation and conditioning for 2 weeks. We then take some samples to test, then add gelatine to fine, and test again.

Left: Low pH FG 1.005 SG

Middle: Regular pH FG 1.005 SG

Right: High pH FG 1.006 SG

Left to Right: High pH mashed beer, Normal pH mashed beer, Low pH mashed beer.

(Before finings)

Note: High pH mashed beer quite dark and cloudy in appearance compared to the lower pH beers.

Left to Right: Low pH mashed beer, Normal pH mashed beer, High pH mashed beer

(Early samples after finings)

Note: High pH mashed beer still quite dark in appearance compared to the lower pH beers. And the low pH mashed beer quite light.

RESULTS

High pH:

Aroma:
Clean, low aroma, muted hop, muted malt, beery.
Flavour:
Muted/low malt flavour, clean, beery taste, medium-low mouthfeel, slightly watery, crisp (odd hop flavour), low-medium bitterness, slight graininess.
Overall:
The taste is very simple, but also not quite right, lacking any solid malt flavour, and had a strange hop flavour with a dryer, slightly sharper bitterness.

Normal pH:
Aroma:
Clean, low aroma, low hop, low malt, beery.
Flavour:
Smooth malty presence with medium mouthfeel, balanced and smooth bitterness, crisp but not drying.
Overall:
Better than the high and low pH beers, with a better malt balance and bitterness. Flavours seem to be more rounded, rather than out of balance.

Low pH:
Aroma:
Clean, low aroma, low hop aroma, low malt aroma, beery.
Flavour:
Malty, bready, beery, medium bitterness, low floral hop presence, smooth with medium mouthfeel, medium but smooth bitterness with a touch of sweetness.
Overall:
Much better than the High pH beer, really solid malt presence with plenty of melanoidin presence adding some bready/toasty flavours. Smooth soft bitterness that balances well.

During the brew day, there weren’t any discernible differences between any of the beers, they all had a post mash/pre-boil gravity of 1.008, and a post boil/OG of 1.010, the only difference observed was a slight difference in FG post fermentation, with the high pH mashed beer finishing at 1.006 compared to the other 2 beers having a lower FG of 1.005.

Comparing the three beers initially without finings, it’s clear to see the impact pH makes in colour and turbidity alone, with the high mash pH being quite dark and cloudy compared to the normal and low pH’s having much lighter hues and clearer appearances. Even after the addition of gelatine, you can still note a darker appearance and slightly more haze in the high pH mashed beer. As for a sensory evaluation, the flavours seemed to vary enough to distinguish, but a drop in mouthfeel/body wasn’t detected in the low pH mashed beer as expected from the implication of cleaving proteins at low pH levels, rather it showed a drop in mouthfeel/body in the High pH mashed beer.

The High pH mashed beer produced quite a muted malt and hop flavour, and a higher/sharper bitterness with a touch of graininess coming through, also having a slightly thinner/reduced mouthfeel, frankly… The high pH mash produce a beer that lacked in nearly every aspect and tasted very one dimensional.

The low pH mashed beer had the biggest malt flavour and a smoother, softer bitterness that allowed some floral flavours to shine through, along with a good medium mouthfeel. The increase in maltiness seemed a little out of place (perhaps more suited to an Oktoberfest/Festbier/Märzen), as the Melanoidin focused malts compensate for this in a regular pH mash and the low pH seemed to enhance these flavours much further. This would easily be corrected in recipe adjustments. Overall I was surprisingly impressed with the outcome of this beer.

The normal pH mashed beer seemed to be the more balanced beer of the three, with a good balance of malt presence not being to overbearing or underwhelming, pairing with a smooth but crisp bitterness that allowed some dryness to come through on the back end as per most Aussie Lagers. Having a respectable amount of body and mouthfeel seemed to be on par with the low pH beer.

CONCLUSION

So what do we learn from this experiment? We can say with certainty that each of these pH levels will produce a drinkable beer (some of course better than others), we should still be aiming for a suitable target around the pH 5.1-5.4 mark for a more balanced flavour profile unless you factor the increases and losses of certain aspects into your recipe development. The results from mashing around our pre-pitch target (pH 4.5-4.7), shows that we can still produce a full flavoured beer that has a richer maltiness, and that could really benefit brewing with such small grain bills. Another point is being such a low pH during the boil, it aids in a smoother bitterness from the hops. It may also help reduce extra steps through the brew day by eliminating acid adjustments and calculations pre-pitch, provided rises in pH from hop additions are factored into the original acidification.

Going forward, it has me thinking… Could lowering the wort pH to 4.7 after the mash and pre- boil yield some better results in terms of reduced hop acid solubility and lower IBU levels, gaining a smoother, more flavourful hop presence? Which seems to be a common issue with many NA/LA beers suffering from excessive harshness from hop bitterness, this could be a key to bettering our processes and having more of a balance of flavours.

If you have any questions, or thoughts about this experiment, or are considering making or testing something similar, please feel free to get in touch with us to discuss your idea and thoughts!

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