Is there a noticable difference between adding extract to all grain and "pure all grain" on high gravity beers?

Question

This may be similar to some of the questions extract brewers ask, but what I want to do is brew my normal 10 gallons, but I want to do an imperial. I use a 10 gallon mash tun, limiting me to 26 pounds of grain, give or take, and I need 40.

I know this is subjective, and will delete if deemed inappropriate, but has anyone done a large addition of extract to an otherwise all grain recipe and perceived a difference?

Answer 1

This is a perfectly fine technique if you don't want to do a double mash session to get it all grain. The only limitation with trying to go "imperial" using a large portion of extract (or doing it all extract if you aren't set up for all-grain brewing) is the fermentability of the extract.

Extract, by nature of how it is made, tends to have a limit to which it can be fermented. Its a function of trying to make the most versatile extract that they can. You may end up with an FG that is higher than you'd like in your final product, simply due to the amount of extract being used.

I can't give you #s because its highly dependent on the brand and amount of extract you end up using.

Here are my recommendations:

1. Use the lightest colored DME you can. It tends to be lighter in color and fresher than most LME sources (unless you have a shop with high turnover). Focus then on using specialty grains for your desired flavor and color.
2. The second recommendation would be to mash in fairly low for the all grain portion. Shooting for 148-149F for 90minutes will make for a highly fermentable wort.
3. Lastly, after you figure out how much extract you think you want to use to get to your desired OG, I'd then substitute 10% of the gravity points from the extract you planned to use for the same # of gravity point with table sugar. Table sugar being almost 100% fermentable will help dry the beer out too.

I have heard of people sparging there grain beds with brewing water that contains a small percentage of their extract in it. Slowly fly sparging that through the grain bed at 160F ish tends to convert the less fermentable dextrans into simpler sugars on the way through the grains. Its sort of an off the wall variable that I don't have a lot of experience with yet, so I am not advocating it, but its something to keep in mind.

Answer 2

As long as you ensure your extract is reasonably fresh, you shouldn't be able to notice the LME in an imperial that's mostly grain. From personal experience, the high alcohol content and heavy hopping rates make it impossible to tell that LME was used. Additionally, stronger beers tend towards higher concentrations of esters, fusels, and other aromatics, which would further obscure any flavors from the LME.

Answer 3

The main difference is that your beer may have a tendency to be somewhat darker depending on the extract and the original grain bill. Make sure you're using fresh extract, especially if using LME since old extract can develop off flavors. Essentially you're just doing a partial mash - plenty of recipes out there that follow that. Beyond that, you'll just run into your typical high gravity concerns such as yeast pitching and hop utilization.