Woops - I added malto-dextrin instead of dextrose

I've been brewing for 22 years and made a bonehead mistake yesterday. When picking up the incredients for a Pliney the Elder clone brew recipe, I bought malto-dextrin instead of corn sugar. The recipe called for 0.4lbs of corn suger and what I added to the boil was .5 lbs of malto-dextrin. From what I've read about malto-dextrin, all it's going to do is add body to my beer (I don't know if a double IPA needs that much body).

The recipe says the OG should be 1.070. I ended up with 1.058 - probably because of the unfermentable malto-dextrin. I pitched the yeast about 16 hours ago and when I checked a few hours ago, it was bubbling away. I'm thinking about buying some corn sugar to add to the primary fermenter. Should I bother? This was an expensive batch of beer with all the hops I had to buy. I'd hate to see it turn out less than optimal.

Boy, that stinks. MD will "thicken" the beer, giving plenty of body. I guess that wouldn't be very good, especially in a Pliny clone. I guess I would boil up some dextrose in a small amount of water, cool and then add.

1.058 seems low, even with MD instead of corn sugar. What was the malt bill?

1.25 pounds of corn sugar in 5 gallons would increase the OG by 11 points, giving you a new OG of 1.069.

On a not-really-related side note, my son used slightly more MD than usual in his root beer recipe. He made root beer Jell-0. So, I'd definitely add some corn sugar to help increase the ABV, and to possibly make up for the MD and the "thickening" it brings. I don't know how much MD is too much, since I've never used it in beer. Maybe someone who has can give some better advice.

First off, malto dextrin won't bring down the gravity. Since gravity is basically amount of dissolved "stuff" in solution. MD in effect keeps the final gravity higher since its not fermentable. You should absolutely add the sugar. Probably up to a pound or more.

Yeah, I agree. Add at least a pound of sugar...maybe a bit more even to get you closer to your intended OG and help dry the beer out (combating the MD addition).

8 oz of MD is a fairly common amount to add when it's used. I don't know the exact effect it'll have on your FG, but a wild assed guess would be 8-10 points.

Thanks for all the advice. The grain bill for this recipe is 11 lb of 2-row pale, .5 lb of Crystal 45 and .5 lb of Carapils. I see that Carapils is dextrin too. The recipe only calls for .4 lbs of Dextrose added at the boil so I likely would not have made it to 1.070 anyway. It called for an 8 gal boil and the runnings were a little thin for the last 2 gallons collected. I just got back from the store with a 4 lb bag of corn sugar and am going to add a pound to the fermenter.