Mash Capping?

[Ben Dean]

I was given the book 'Modern Homebrew Recipes' by Gordon Strong as a christmas gift. In it he goes into a bit of detail about 'mash capping' - only mashing fermentables then adding crystal/roasted grains etc to steep for the last 15 min of the mash, the main purpose of this being greater control over mash PH during conversion. Has anyone here tried this method and if so, what was the outcome? Did it work for you? Do you mash cap for every brew? Keen to hear of anyone's experiences with this.

Cheers

Ben 

[Grant R Baker]

hmmm... interesting idea. I have seen it done but not for that reason.

Crystals warm steeped (for 30minutes) and dark malts cold steeps (for 12-24 hours) then the liquid added to the mash near the end for a smoother taste, less astringency especially off the dark malts.

I am in the process of converting to rain water for brewing and have been review the Ezi_calculator recommendations for pH levels with differenent beers.

If you adjust water pH to try and hit the perfect mash level wouldn't the liquid then lower the pH when added..?

The mash is over so no issue with that but the beers acid level would be higher..?

I probably have more questions the answers... haha

[Crusader-Rob]

My view - Mash Capping does not really work when adding crystals/roasts to the mash at the end, on the basis that your still doing a warm/hot extract, it becomes somewhat irrelevant in some respects if you add the specialties at a later point, as the hot liquid will still extract this type of flavour.

It does however work quite well when using dark malts, and adding the dark liquid in the boil, but this is still limited, as some roasted flavour still comes through, but as grant suggested, it is smoother.

just my 2 cents.

[Ben Dean]

Interesting link Chig, thanks for sharing.

The thought behind mash capping for better control over mash PH is that you don't have to account for speciality grains affecting the PH level of your mash, as by the time you add them the conversion of your base malt has already taken place. If you have a 'go to' base malt that you use each time you brew and use the same water each time, you can dial in your water additions/acidulated malt % over a series of brews. Once you have this dialed in you can hit/get very close to your target PH every time regardless of what speciality grains you are using.

I haven't tracked my mash PH before, I've just bought a meter so I can start when I next brew. I find the subject quite daunting, the mash capping idea simplifies the process (in my head at least) which is why I'm drawn to it.

[oliver]

I've been doing this for a while with stouts for 2 reasons: 

1. To keep mash pH a little higher during the bulk of the conversion process.

2. To reduce roast/astrigency extracted from the roasted malts.

This is purely anecdotal, I haven't done any side by side experiments:

I've found adding the dark malts at the end of the mash does give me less astringency, more emphasis on the chocolate type flavours which works nicely with paler choc malts. I've also found you get less colour. 

Sometimes when doing stouts I'll add enough spec malt to bring the mash ph down around 5.4-5.5, then add carbonates + the rest of the spec malt at the end of the mash. I also do quite a long batch sparge process, so you might get quite different results if you're just doing a quick biab sparge say. Crush probably also affects what impact using this technique would have I'd imagine.

Along the lines of what Grant was saying about pH, I have done some stouts where I've used acid to drop mash pH, then once I've added my dark grains I've struggled to get the pH back up, ending up with a post boil pH of around 3.15. So I'd watch out for that if you're going to try this.