OG too low?

[Koop]

I brewed Jamil's Amber Waves extract plus grains recipe (from the November BYO issue) twice this week. The first time I used the amounts exactly as listed, the only difference was substitution of Briess Light LME instead of Alexander's and Weyermann Munich malt instead of Durst. Here's the fermentables for a 5 gallon batch:
6.0 lb Light LME
.75 lb Crystal Malt 40L
.5 lb Munich Malt
.25 lb Crystal Malt 120L

His recipe states OG is 1.051. I boiled 5.5 gallons and ended up with 4.5 gallons. I topped up to 5 gallons then stirred briskly for 10 minutes and aerated. My OG at ~74f was 1.044.

On my second batch I upped the light LME to 6.6 lbs and made a hop adjustment. All else remained the same. My OG at ~74f is 1.042.

I checked my hydrometer with H2O and it's accurate. What's up?

[Bugeater]

You appear to be suffering from one of the most common problems experienced by relatively new extract brewers. I am 99.999% certain that you did not stir in your top up water as good as you thought you did. The extract is heavier and sinks towards the bottom. You most likely took your sample from towards the top. This will give you a lower apparent OG.

For extract or extract plus steeped grain recipes or kits you are best off just using whatever OG they say it is supposed to be or to compute it yourself. It will be more accurate than trying to actually measure it.

There is nothing wrong with your OG, it is where it is supposed to be.

Wayne
Bugeater Brewing Company

[Koop]

You appear to be suffering from one of the most common problems experienced by relatively new extract brewers. I am 99.999% certain that you did not stir in your top up water as good as you thought you did. The extract is heavier and sinks towards the bottom. You most likely took your sample from towards the top. This will give you a lower apparent OG.

For extract or extract plus steeped grain recipes or kits you are best off just using whatever OG they say it is supposed to be or to compute it yourself. It will be more accurate than trying to actually measure it.

There is nothing wrong with your OG, it is where it is supposed to be.

Wayne
Bugeater Brewing Company

I've heard this "stratification" theory before. I took my sample with a thief that reached well into the primary, probably closer to the bottom than the top. That coupled with nearly identical readings from two batches has me wondering. Could the recipe in BYO be miscalculated?

[Bugeater]

I just ran that first recipe through Promash and came up with 1.050. That pretty much agrees with what your recipe said. I then did the temperature correction on your reading. 1.044 @ 74° = 1.046 @ 60°.

Then I got to looking at the ingredients. Did you mash or steep the grains? Munich has to be mashed to convert the starches to sugar. If you just steeped it, you will get virtually no sugar contribution to the OG from the Munich. I dropped the Munich out of the recipe and the OG dropped to guess what? 1.046!!!

If that wasn't it, then I haven't a clue as to what happened to your OG and we will have to pass this dilemma off to someone with fewer dead brain cells than me.

Wayne
Bugeater Brewing Company

[Koop]

Thanks for doing that Wayne. The instructions call for steeping of the grains for 30 minutes starting at 170f. I wondered about the Munich. I did deviate on the second batch, I added the grain bag at 145f and brought the temp up to 165 and steeped for 30 minutes. It probably didn't make any difference as I didn't hold for any length of time between 145 -155f.

[Bugeater]

That one had me stumped for a bit. Next time hold it for 20-30 minutes around 150°-155° to get the munich to convert and your OG should be up where it should be. Glad to have been able to help.

Wayne
Bugeater Brewing Company

[BDawg]

Great detective work, Bug!

The issue here (that hasn't been explicitly stated) is the steeping temperature. Above about 160F or so, the heat will denature the enzymes (just like an egg white, the enzymes "cook" and won't work any more). That stops any conversion in its tracks. That's WHY Bug is telling you to steep at the lower temperature.

HTH-

[Koop]

Great detective work, Bug!

The issue here (that hasn't been explicitly stated) is the steeping temperature. Above about 160F or so, the heat will denature the enzymes (just like an egg white, the enzymes "cook" and won't work any more). That stops any conversion in its tracks. That's WHY Bug is telling you to steep at the lower temperature.

HTH-

Thanks BDawg. I understand starch conversion and I knew the crystal malt didn't require it, you can just steep the sugars out of it. Munich on the other hand requires conversion. The recipe in BYO says;

"Mill or coarsely crack the specialty malts. Mix them well and place loosely in a grain bag...Steep the bag in about 1 gallon of water at roughly 170f..."

I wonder why they wrote the recipe like that? If I would've really thought this out I would've steeped the bag at ~150f for 30 minutes. I'll chalk it up to experience and try that next time!