Cold Mash To Lower PH

[TNP]

Apparently farmhouse brewers prepare the mash with a little cold water the evening before brewing. This Is thought to lower PH. Ever tried this?

 

[dmtaylor]

This is known as the "acid rest". I have done this but not certain what impact it has -- I have not experimented with it directly. But I'm sure it must be beneficial in some instances, otherwise the concept and the term would not exist.

 

[Dorst]

Define cold water. I've learned that mashing in too low (I think ancient brewing knowledge says 35 to 38C) leads to oxidation of your malts and unpleasant flavours.

As dmtaylor says you can acidify your mash by a short mash step between 35 and 44 degrees.

If you know your water chemistry it's easier and more consistent to just add the amount of lactic acid that your brew software / calculator tells you to ;-) I really like Brewfather brew software's implementation of this feature.

 

[Sadfield]

As above, you can do a short acid rest utilising Phylase. However, I'm not sure this is what is being alluded to here. Where is the 'Farmhouse' reference from? It sounds more like a long soak for cold extraction and probably Lactobacillus activity.

 

[MashBag]

This is something I do all the time.
I have a 9 hour cold mash. I certainly have found nothing detrimental possibly just the opposite to be honest.

 

[TNP]

I know about acid rest but It's not that. I mean cold water, about 5 C.
In his book about traditional farmhouse methods Garshol mentions this as a relatively common practice among farmhouse brewers. And as with many traditional methods they don't really know why they do that, only that It works. Garshol then comments that this nightlong "bath" lowers PH, but doesn't elaborate further.

I too thought about lacto activity, cold and short enough as to not sour the mash (It's not that easy to do a sour mash) but enough ti lower PH.
Would be useful, or at least interesting, to know the math behind this to effectively and consinstently use it

 

[TNP]

This is something I do all the time.
I have a 9 hour cold mash. I certainly have found nothing detrimental possibly just the opposite to be honest.

Would be interesting if you could take a PH reading during a brew day after this cold mash and compare It to the expected pH... (I'd do that myself but don't have a pH reader, although May buy a cheap one just to try)

 

[Sadfield]

I could well imagine a farmhouse brewer doing it just to get a headstart on a brewday. Then continuing to do it as they discovered they got a stronger beer, better flavour or such like.

 

[TNP]

I could too because I was close to do the same thing for my last brew, but in my case I was more worried of actual bugs than sourness

 

[MashBag]

Mine is a cool soak @ 20c (outside acid rest territory) I have noticed stronger beer. So much so that I reduced the grain bill by 500g (23l)

I do it for timing reasons and don't really have a brewday now.

 

[Agentgonzo]

Mine is a cool soak @ 20c (outside acid rest territory) I have noticed stronger beer. So much so that I reduced the grain bill by 500g (23l)

I do it for timing reasons and don't really have a brewday now.

I'm curious as to what chemistry is going on in the background with this. Sounds interesting and no something I've heard of before

 

[TNP]

There's also this little thing called non-enzymatic mash: you mash cold overnight to extract body, flavor and just a bit of fermentables to get a very low alcohol beer.

Could be related?

 

[MashBag]

It is something I have not thought about. I liked overnight mashing as a concept, but didn't like the idea of a 12h leccy bill.

20°c is is the coldest my BM will go. From a chemistry perspective, I don't know. I have always assumed it to be just a simple soak. Fully soaking the grains. Interesting....

 

[MashBag]

Found this....

https://www.brewingwithbriess.com/b...onents-and-their-use-in-brewing-applications/

 

[TNP]

Well if It's really just cold extraction and pH Is not related then It's nothing new... It's what I do with my tea.

 

[crescent city Mike]

The "dough-in" is an old traditional mash step but the term is normally misused today. With under-modified malts and decoction mashing, it really was a big deal. The original dough-in was just that – a small amount of water was added to the grist and it was kneaded like bread dough. Many references call for using ambient temperature water but other references state “warm” water. The dough-in phase could last for hours and allowed the grist to hydrate long before the alpha and beta amylases got to work. Today, the mash-in is done at almost any starting temperature and allows the grist to hydrate with or without amylase activity.

In the days before high tech gadgetry like the thermometer and hydrometer, brewers would mash-in or raise the dough-in temp by infusion to “blood temperature” of about 99o. All they knew was that it worked. Science has determined that phytic acid is produced from phytin in the malt by the enzyme phytase. Phytin is a calcium/magnesium phosphate. Generally, the paler the malt, the more phytin it contains. This weak acid brings the pH of the mash down to reasonable levels so the other enzymes can do their jobs efficiently.

Both of these "rests" were a lot more important with the under-modified malts of the time.