What is the harm of diluting/no full boil

I remember from my extract days that one of the big upgrades was the ability to do full-volume boils, which I have been doing for 50+ batches now.

We have a 7 month old, so my objectives for brewing have been revised from simply “brew the best beer possible” to “brew the best beer possible, while brewing as much of it as possible when I get the chance to”.

So I was thinking of basically maxing out the 20-gallon mash tun every time we brew, then diluting (either pre-boil or post boil) depending on how much capacity we have between our 30 gallon boil kettle and my 10 gallon.

What are the main disadvantages to diluting the wort post-boil? Just hop utilization?

You could end up with darker colored beer, similar to what happens with concentrated extract boils.

If you are brewing very light beers, you will be replicating what some big breweries do. They will do a concentrated boil, then a concentrated fermentation, and only dilute when they are about to bottle. The stated rational is that you get a better malt flavor when the fermentation is done that way, but I suspect it has more to do with fitting more beer into existing tank capacity.

It’s mostly just a color thing. There might be a more noticeable effect on color when you plan to make a really light color beer like a pilsner or kolsch, but if you can do an almost full boil then you might not even notice much difference. Flavor impacts should be negligible. If you need to concentrate your boil slightly, go for it. It will turn out just fine.

I think pH is a factor. Maybe you’re OK using distilled or pH adjusted water, but even then I can’t help but think a 50/50 dilution would have negative effect. I mean seriously, can one take a can of HT and dilute it 50/50 with distilled to create a session beer? That said, 10-20% might be OK. I think even just 10% tap water that is a high in alkalinity could be a disaster though…

our tap water is 7.9 total alkalinity, but if I am adding pre-fermentation, wouldn’t the yeast drop it pretty significantly even if alkalinity is significant (which I don’t believe it is)?

Hmm… where’s Martin when you need him… :slight_smile:

You might be OK with that low of alkalinity. (lucky!)

Sorry got thinking post ferment… Rebuilt, any idea how much the dilution is?

[quote=“zwiller”]You might be OK with that low of alkalinity. (lucky!)

Sorry got thinking post ferment… Rebuilt, any idea how much the dilution is?[/quote]
About 20%. I just did one of these, in part because I was curious if the effect was real. Still lagering though, so can’t report on the results.

Another option is to brew a bigger beer and dilute it down at bottling. This is what all the big brewers do. Here is the reference information I use:

When I use this technique I dilute with distilled water from jugs that have not previously been opened to guarantee that the water is sterile…

I dilute post boil because I have the room in the fermenters not the boil kettle. I boil the water and run it though my chiller sort of a pre-rinse before it gets cleaned at the end of the brew day. I have diluted up to about 32%.

We ended up maxing out the 20-gallon mash tun, then diluting pre-boil as the boil kettle is 30 gallons. I brewed a highly dextrinous, unhopped beer on my 5 gallon system, and blended with the diluted pilsner in the flanders fermenters, so we ended up filling the 14-gallon conical with pilsner, and 2 6.5-gallon carboys to about 5 gallons each, splitting the flanders cake between the two along with some brett trois (sacc trois). Gettin’ freaky.