Recently looking at the AHA Big Brew Day Recipes, I was looking at the Old School Barleywine (pdf). I get the hops schedule, but the fermentables has me confused. In the instructions, it says mash at 152 F for 90 minutes, I get that. Then mash out at 168 F for 15 minutes. I'm not sure I get that. Perhaps I don't understand really what a 'mash out' is. (That is a subject for another question.) My question here (and perhaps it relates to the mash out) is that it lists grains for both the mash and the vorlauf. I'm wondering how these two are related, specifically, how are grains used in/added to the mash while starting the vorlauf? Are they added while vorlaufing (is that a word?)? I can't ever guarantee how long a vorlauf might take, so is this related to the 15 minute mash out? Relevant recipies and instrutions below...

12 lbs (5.4 kg) 2-row malt
6 lbs (1.4 kg) Maris otter malt

8 oz (227 g) Caravienne® malt
8 oz (227 g) Crystal 40 malt
4 oz (113 g) Crystal 65 malt
2 oz (57 g) Crystal 120 malt
2 oz (57 g) Special B malt

Mash grains at 152° F (67° C) for 90 minutes
Mash out at 168° F (76° C) for 15 minutes,
with pre-boil wort volume of 6.5 g (25 L)

2 Answers 2


Consider a batch sparge in this scenario: the wort from the 90-minute mash is drained and the grain is rinsed with a 168º mash-out infusion (or two) to collect residual sugars. Typically, this water can be dumped into the mash tun, stirred a bit, then collected. In this case, rather than the usual "dump-n-drain", the "Vorlauf" grain would be added after collecting first runnings, followed by the mash-out infusion(s). Wait 15 minutes, drain, boil wort as usual.


"Mash out" is a step to denature (kill) the enzymes in the wort so that they don't keep working during the vorlauf/sparge etc. You are 'locking' the fermentability at a certain point, to preserve some dextrins so the beer will have body.

Sometimes grains will be added after the mash to get some, but not all, of the character from them. For example, very dark grains (like the Special B) are often added this way to give color without the astringency.

Adding the crystal malts at the end of the mash is a little unusual, most brewers put them in the mash as they have some starches to be broken down. But the sugars (the crystals) will dissolve readily, giving the crystal malt flavor. Maybe the intention here is to also get some starch into the wort, just to make sure this 1.109 beer doesn't end up too thin...

I think the 15 minute time is given just to make sure the enzymes are fully denatured. A little longer would be OK, but would could add more tannins to be wort.

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