Up Coming First AG Session - Questions/Clarification needed

[Damoxemus]

So yeah, gonna do my first AG this weekend. Probably a Porter from the Recipe section.
I've read Hot To Brew, did an assist on an AG batch a few months ago and have read through quite a bit of the stickies and other threads. I still have a couple questions though.
I have a new 9 gallon kettle with temp probe and 3 piece Ball lock valve, and a 10 gallon Igloo MT (Round). I plan on doing a 5 gallon batch.

First Question: I've read that putting only 10-15lbs. of grain in a such a big cooler can lead to it losing temp during the mash. Should I get the water a bit hotter, or put some aluminum foil over the grain bed while it's mashing. Can't remember where I heard about the latter but seems worth a shot.

Second Question: Determining Efficiency - Before I start the boil f I'd like to know what the efficiency of the mash is. That way if it comes up short I can add some DME at the end of the boil. We did this on my first day with a refractometer, which I do not have. Should I just cool some to room temp and check with my hydrometer? If so, are there any tips on how to do this quickly/efficiently?

Any other tips would also be great appreciated.

Thanks!

 

[GASoline71]

I use a 10 gallon Igloo cooler and mash anywhere from 8 to 15 pounds of grain and have no probs with temp loss. No extra gadgets needed. I put 3 to 4 gallons of hot tap water in my cooler MT before I start my strike water up to the target temp. When the strike water is ready I dump the tap water out, and fill the cooler with the strike water. That way the cooler is more "up to temp" prior to the hot strike water hitting a cold MT.

Gary

 

[stevehardt]

I do the same as Gasoline. Preheat the tun with hot water while you're getting your strike water to temp. Then dump the initial water, and add your grain and strike water. Stir it up real good, check your temp, then close and cover the tun. You really shouldn't lose a lot of heat after this.

After I let the mash sit for the designated time, I drain my first runnings. Then I batch sparge to get my remaining volume. Once I have my full pre boil volume I take a temp and hydrometer reading, and temp correct. If I'm way off (and only if I'm way off) my OG, I add DME.

While my efficiency could always be better, I'm pretty consistent. Barring problems with my crush, I hit OG or fairly close, so I haven't had to add DME yet.

Just how I do it

 

[brewkinger]

Like the others said, preheat the cooler with some hot (not boiling, it can warp the cooler) water and then dough in.
Stir up very well and cover. Wrap with a sleeping bag or blanket/coat if you are really worried. You should not lose much heat if any at all.

As far as checking efficiency without refractometer, just get a large enough sample and cover with a piece of Saran Wrap and stick in fridge until around 70 degrees and then check with hydro.
I prefer to wait until post boil to check and add DME then to bring gravity up before chilling.

 

[Damoxemus]

Thank you folks, much appreciated.

I think I pretty much have it. Just need to calculate water temps etc. and should be good. I'll be getting Beersmith tomorrow to play with a bit before hand.

 

[scorpien222]

Would I be right in thinking that taking a sample pre boil will be way off your expected OG ? So how do you determin what the gravity should be post mash but pre boil ? I have been having a problem with missing my expected OG.

 

[brewkinger]

Each grain that is mashed has a maximum potential of gravity points per pound.
Example recipe:

5# of base malt (max 40 points per pound of grain)
5# of other malts (max 35 points per pound)

5 * 40 = 200 pts from base malt
5 * 35 = 175 pts from others

Gives a total of 375 pts and assuming a 6 gal pre boil would be 375 divided by 6 would be roughly 62 points.

So the highest gravity that we could get in 6 gal of pre boil would be 1.062.

This is how efficiency is figured too. If we make that recipe and get a 6gal pre boil gravity of 1.050 then:

50 out of a possible 62 points extracted would be 80.6% mash efficiency (this would be good by the way)

 

[Mudgrunt]

I'm about to start going the AG route myself and this is a very helpful piece if information. Thanks for the knowledge!

 

[Damoxemus]

Well, I did the batch on Sunday and it went pretty smoothly for the most part. Especially since I was using all new equipment.

Going by the formula above I got about 65% efficiency. Not great, but not bad for my first go.

Thanks again for the tips!