Low Pre Boil ph after overnight mash

[Skittlebrau]

Mashed a Doppelbock on Sunday morning, mash ph was 5.4 with no pH adjustments carried out. The mash was left covered on top with insulation around the mash pot. Was due to do the boil Sunday evening but didn't work out.

Took a pre boil pH on Monday and it was reading pH 4.0 Double checked the pH meter calibration and took extra samples of the wort but still getting pH 4.0. Did a boil to see if the figures would shift and got pH 4.2. The final wort og is 1.076 yet the wort tastes sharp and unpleasant.

I don't normally leave over a day between the mash and boil, has anyone seen such a large shift in pH like this?

[nigel_c]

That's some ph drop for such a short period.
If your planning on boiling the next morning you should complete the mash, mash out at a decent temp to denature and kill off the lacto on the grain that caused the drop.
I split my Brew day a lot of the time and have never had any problems with this method.

What you have now is a prttty high abv kettle sour.
If your keeping it you may need to think about what yeast will work in that ph range.

[Skittlebrau]

Thought there might be a slight drop in pH but nothing this drastic. In hindsight, I should have mashed out on Sunday    Will start it going forward for overnight mashes.
The wort will get binned as I don't think much good will come of it.

Nigel_C, do you ever check pH after an extended mash period? Curious to see if there's typically much shift in the value

[Raxy]

http://brulosophy.com/2018/01/08/mash-length-overnight-vs-60-minutes-exbeeriment-results/

No mention of the pH of the mashes but here's an extended mash experiment.

[Skittlebrau]

http://brulosophy.com/2018/01/08/mash-length-overnight-vs-60-minutes-exbeeriment-results/

No mention of the pH of the mashes but here's an extended mash experiment.

Interesting read. As you say, there's no info on the pH after mashing overnight. Wonder was there any difference.

[Simon_]

Did you do a mash out step?
Are you sure your pH meter is calibrated?

[Skittlebrau]

Didn't do a mash out. Don't expect any issues with the pH meter reading but I've pulled another sample and going to cross check it against a second pH meter to be sure.

[nigel_c]

I don't recall and drop in ph but ill defo check next time I do it.
A good mash out in necessary otherwise your basically doing a sour mash. There is a lot of lacto on the grains to do their thing as the temp drops.

[Simon_]

You can avoid this in future and manage an overnight mash by doing a mash out or hold the mash temp for the whole duration or at least keeping it over 50°.
More than 24 hours is a bit much though.

[Skittlebrau]

It's measuring pH 4.06 on a second pH meter.