Acid Rest?

[blackbock]

Hi

I've been having some problems getting my mash pH low enough (untreated water pH nearly 8...)
and during some research on the possible remedies, I wondered whether many people have ever tried using an acid rest (instead of using, say, acidulated malt, or direct acid additions to correct the pH)

So. Is it worthwhile giving it a try? Seems easy enough. No calculations involved.

 

[Weizguy]

Apparently, according to Palmer here, the phytic acid rest may take several hours to bring the pH to the optimum level of 5.0 - 5.5, staring with clean , neutral Pilsen water.

Maybe it would take longer with your water. I'd recommend starting with an addition of 200 - 500g acidulated malt, instead.

You would definitely have to experiment with the acid rest time to see how long it takes to get to your target pH.

If you leave the mash too long, you could start to get some lactic acid being produced by the lactobacilli which inhabit the barley husk, even though the temp is below the 50 C mark, which is about their preferred temp.

As documented elsewhere on this forum, I recently commenced an acid rest for over 24 hours, from an initial 38 C. The wort eventually dropped down to about 14 C despite insulation, and began to smell sour. This is what I was after, but it may be less than the ideal way to perform the biological process. Anyway the wort was boiled for 120 min and should have no residual acid activity.

I hope this helps.

Acid Seth

(* edit: smelling)

 

[Kai]

Hi

I've been having some problems getting my mash pH low enough (untreated water pH nearly 8...)

What's the pH of your mash usually?

 

[blackbock]

around 5.9

 

[wessmith]

Hi Blackbock, 5.9 is too high and you need to get this down around 5.2 to 5.3. Forget the acid rest as Seth indicated and go for some acidulated malt - usually around 1 to 2% of the grain bill, but this will depend on your water and the calcium content/hardness.

Wes

 

[unrealeous]

Digging up an old thread but I'm brewing a pilsner this morning so I thought I give the acid rest a go.

I can't find much info to people doing it on the internet - most of the advice on the internet is "dont bother", "use aciduated malt", "use an acid addition", "use salts" etc etc... Even our mate John palmer doesn't recommend it "The acid rest is not used nowadays because it can take several hours for this enzyme to lower the mash pH to the desired 5.0 - 5.5 range. Today, through knowledge of water chemistry and appropriate mineral additions, proper mash pH ranges can be achieved from the outset without needing an acid rest."

But being time wealthy, adding a couple of hours to a brew day - especially all my mashing steps are now automated.

I've just calibrated the ph meter - will see how much it drops in a couple of hours

Interesting to hear if anyone still bothers using it.

 

[unrealeous]

5.8 down to 5.5 in 2 hours... might let it run a little longer

 

[Bribie G]

Interesting experiment, let's know how it goes - I use acidulated malt in BoPils but always interested in the old ways.

 

[Thirsty Boy]

remember - sometimes "acid rest" refers to a ferulic acid rest when making a wheat beer. So if you were reading about "joe blow does an acid rest for all his weizens..." then they probably mean something different.

Interested to see just how long it takes to use a rest to drop to acceptable mash pH though - thanks for taking one for the team.

No concern that enough lactic action to drop the pH could also result in noticeable funky flavours?

 

[blackbock]

Hi unrealous,

I am excited to hear about your experiment. I decided against using this technique a long time ago as it seemed to offer little advantage and lengthen an already laborious brewday for BoPils... I will be interested to hear what you think of the result. I hope you are not triple decocting as well for your sake ;-)

 

[unrealeous]

2.5 hours - 5.8 down to 5.4-5.5

My ph meter is a bit of a cheapy - it probably +/- 0.1 at least per measurement. Next time (I'm brewing again tomorrow) I do it I'll take a sample at the beginning, put it in the fridge so I could do side by side comparisons at the end.

However, its pretty painless - I programmed in the steps - turned it on and instead of taking 2 hours to do the mash - it took 5 and a half. Checked it every now and then - seemed to be happy.

Its just landed in the fermenter now.

 

[speedie]

we always use a three step program in mash pratice first 45-54-62 through to 71
which ever meets the fancy on the day for sacrification area
why would anyone with the malted grain of today do a decoction mash now days
speedster
ps inprove the head retension

 

[speedie]

tb are you referring to the effects of lactobacillus
that belgium trait
no i think not
acid rest is acid rest
probablily not required with modern malting

but i still include this important area of temperature mashing
enigma

 

[NickB]

Uuuuummmmm.....

yes, well.....

Ahem.

 

[blackbock]

why would anyone with the malted grain of today do a decoction mash now days
speedster

Possibly for some of the same reasons why they might do an acid rest! It's not always about the end result...

 

[unrealeous]

why would anyone with the malted grain of today do a decoction mash now days

I think that was asked as a rhetorical question - we might need to send speedie to on a course in punctuation. And I'm reading decoction mash as multi-step mash since there are many ways to skin a cat.

However, some good did come out of all of this - the page on decoction mashing has some stuff on acid resting.
http://www.homebrewtalk.com/wiki/index.php/Decoction_mash

 

[Bribie G]

The wiki then goes on to say that the protein rest depends on the degree of modification of the malt, as speedie was referring to. However I assume that an acid rest can be followed by a sacch. rest and no need to do the protein rest. With pilsners nowadays I do a Hochkurz mash (three stage starting at 62 degrees - dead easy to do with BIAB) with acidulated malt. I'll have a crack at an acid rest in a couple of weeks when I do my Carlsberg-style lager. Just for the hell of it.

To the OP, I have a pack of pH strips but not a pH meter, would they be sensitive enough to monitor an acid rest?

 

[blackbock]

Good quality pH strips and a good eye are just as, if not more accurate than electronic gizmos Bribie

 

[Thirsty Boy]

tb are you referring to the effects of lactobacillus
that belgium trait
no i think not
acid rest is acid rest
probablily not required with modern malting

but i still include this important area of temperature mashing
enigma

No, i am referring to a rest which targets the production of ferulic acid, which is the precurser to 4VG or if you prefer, the clove tasting phenol, in a wheat beer.

The acid rest primarily being talked about in this thread is about the action of a combination of enzymatic action and the production of lactic acid by lactobacillus (motly the lacto IMO) for the purpose of lowering the mash pH.

So in fact, an acid rest is not an acid rest, it could be for two different reasons and mean one of two different things. I mentioned it only because a lot of people who step and/or decotion mash, do it on their wheat beers but not so much on other beers - and in the instance of wheat beers, there is a fair chance that any "acid" rest is supposed to be about making a beer that tastes of cloves, not so much about lowering mash pH - and they mighht be inluding the "other" acid rest as a traditional step that doesn't really exist.

 

[_HOME_BREW_WALLACE_]

tb are you referring to the effects of lactobacillus
that belgium trait
no i think not
acid rest is acid rest
probablily not required with modern malting

but i still include this important area of temperature mashing
enigma

Sorry to the Op'er...... Speedie mate, i think YOU! should have an acid rest......