Concerning maximum possible pre-boil gravity

I was recently listening to the High Gravity episodes of Brew Strong and a couple of questions came to me. Unless I was misinterpreting multiple times, it seems like they were saying that the maximum pre-boil gravity attainable with all-grain, within normal mash thickness, is something like 1.075-1.080. Well, ok, that makes sense, since adding more grain means you need to add more water (assuming you're trying to keep a consisten mash thickness). They more or less seemed to be saying that to get into really high gravity brews (1.100+) you're going to need to add either extract or simple sugars to the boil.

That really confuses me for a few reasons. First, just looking through recipes here on HBT, I see plenty of recipes put up that have OGs over 1.100, with no extract additions, and only a 60-90min boil. If the maximum possible pre-boil is 1.075-1.080, it doesn't seem to me like you would be able to boil off enough to hit a 1.130 gravity, for example.

Secondly, I've been reading a lot about Sahti recently because I brewed a recent batch. The Brewing Techniques article I pulled a lot of my information from states that Sahti is traditionally no-boil, but that OGs can be over 1.100 even with all malt. Again, how is that doable? Is it just a result of unusually thick mashes? That would help but would seem counterproductive as your ability to convert would be impacted.

I'm probably just thinking about things incorrectly, so if someone could sort me out I would appreciate it.

This is the exact same question I asked a while back. There was never an agreed upon answer, however, I have heard of 1.090+ first runnings.

My highest first runnings have been around 1.080

However, you aren't just limited to those two options. I usually boil down to the needed Pre-Boil gravity before adding any hops to the addition.

Here is my old post:
https://www.homebrewtalk.com/f36/maximum-og-mash-189764/

Here is a chart that was mentioned on my thread that says you can get higher than 1.18 on your first runnings. It looks like you just need one hell of a thick mash (And a very long sparge).

http://braukaiser.com/wiki/index.php/File:First_wort_gravity.gif

Oh wow you weren't kidding, our posts are damned near the same! Thanks for linking to it. Yeah, it really doesn't seem like there was an agreed upon answer. It's just that these recipes with huge OGs, that have no mention of mash or boil volume really confuse me.

Thanks for the links!

shanecb said:

Oh wow you weren't kidding, our posts are damned near the same! Thanks for linking to it. Yeah, it really doesn't seem like there was an agreed upon answer. It's just that these recipes with huge OGs, that have no mention of mash or boil volume really confuse me.

Thanks for the links!

Click to expand...

All of my high gravity beers get boiled down to the proper SG. If you can't hit your numbers from the first running, then that's really the best answer I can give you.

I don't like the idea of using DME since that is possibly destroying the balance of any specialty malts (depending on the amount needed).

I don't like using DME much either, but for very high gravity beers a little extra light DME goes a very long way. Just my 2c.

Very interesting about the 1qt/lb producing 118GP. I have a feeling that this is possible, but that you don't get a lot of first running so it's basically just highly concentrated syrup.

Here is another link:
http://onebeer.net/boilcalc.shtml

I use this calculator to find out how much I need to boil-off to get to the proper SG before the hop additions.

Yup, 1.120 is about the best you can do but it will cost you a TON of grain so you better be getting a sparge runnings beer out of it.

Grain absorbs about 1/2 quart per pound so when you start with .9 quarts per pound ratio, the available runoff is reduced to .4 quarts per pound. If you want 7 gallons (28 quarts) preboil, you'll need to use 70 pounds of grain.

Going more conservative is more practical. SHoot for 1.15 qt/lb for a max of 1.102 SG and now for the same 7 gallons preboil, you'd only need 43 pounds of grain.

In these extreme cases, it's more economical to boil longer or augment with sugars than to keep throwing more grain at the problem.

Makes sense. I typically add DME to the mix when I'm shooting for something particularly high (or simple sugars depending on style). Thanks for the help everyone. I'm still mildly confused about the Sahti thing. The only thing I can think of is like what you said Bobby, they just use much more grain to get, e.g., 5 gallons of wort than I thought they would.