60 min mashes - do they work!?

[Jambo]

Hello

I never hit a recipe's target OG if I only do a 60 minute mash (specified in such recipes). I never have any problems with 90 minute mashes.

The simple conclusion is that I should do a minimum of 90 minutes whatever the recipe says, but I'm keen to understand what is going on.

Can anyone explain in layman's terms to what extent mash efficiency is time related?


Cheers.

[TheSumOfAllBeers]

If your mash pH is off the sweet spot, enzyme action can work slower. Conversion may not be complete by the end of the 60 minutes.

That is one source of missing your numbers.

[McMullan]

I'm guessing the water is pretty soft in your neck of the woods, Jambo. Do you add any calcium (calcium sulphate or calcium chloride) to your brewing water? That can help get the pH to the sweet spot. I know a lot of people who prefer a 90 min mash, because of the increased efficiency. Most of the available malt sugars are converted within 30 min or so. What remains to be converted just takes time. You could do a 120 min mash if you wanted to. I think it comes down to diminishing returns on time invested. There are so many variables involved, I read recipes as guides and adjust where I can for my brewing kit. As long as the end product is good, I'm happy.

[Mr. Dripping]

I've mashed for as little as 35 minutes and not seen any drop off in efficiency....this was at 71 degress C as well.

Modern malts are so good these days and so well modified that conversion is complete very quickly. The length of mash time will affect the fermentability of the wort, with longer rests favouring drier beers (ie lower FG).
Poor efficiency IMO is more likely to be related to mash pH or lack of calcium.

[Jambo]

Thanks for the pointers everyone.

I have never dabbled with tweaking my water at all. I got a water report last year which said 19 mg/L of HCO3 for alkalinity - is that low?

As I said in the original post I guess for now 90 minute mashes fix the problem, but any pointers on water tweaking.

Thanks

[McMullan]

19mg/L is pretty low. You have soft water, which is a good thing, IMO.

Next time you brew add a tsp (per 23L batch) of calcium sulphate (gypsum) or calcium chloride to your milled grains. Then mash in. There is a good chance it'll improve your efficiency with a 60 min mash.

Adding calcium is good place to start tweaking your water. You might find that is all you need to do. (Get a water report from your supplier, before tweaking anything else.)

The boring bit: A typical mash of malt in pure water has a pH of about 5.6. Introducing calcium helps lower it to about 5.2, which is supposed to be the optimum pH for amylase activity.

[Jambo]

Thanks McMullan I'll give that a bash!

[Jambo]

Well I gave this a go and have the following observations
- Met the target OG with no issues whatsoever albet with a 90 min mash specified in the recipe, not a proper test for my 60 minute issue, but 90 min mashes can be a struggle sometimes too.
- Wort was notably brighter when draining from the mash tun after just a couple of pints being recirculated
- I think for the first time in my AG brewing career I actually saw a proper hot break and cold break and the wort falling bright
- Fermentation seemed to be over much quicker than normal

Do all these seem reasonable observations from throwing in a teaspoon of CaSO4 or am I imagining stuff?

I'll order up some pH papers and try to put some science on this.

[Jocky]

I've been experimenting with 45 min mashes recently.

To be precise, I'm doing a 45 min single infusion mash and then I add hot water for a combined mash out/sparge at the full volume and recirculate for 15 minutes before draining. My mash is usually in the sweet spot range of 5.2-5.5 and I get a mash efficiency of 70-75%.

This is my run off:

And here it is again post boil: