Looking for process improvement suggestions

Question

I just did my 4th brew, my OG was lower than expected, and I'm looking for help with process improvements. I'm doing an all grain process. I have an 8gal kettle, a 2gal kettle, and a 0.5gal kettle. For the mash tun I have a 10gal home depot converted cooler with ball valve control spigot.

My process is as such:

1. Day before - fill the kettles with water, let them sit 24 hours with a Campden tablet shared between the pots.

2. Heat 6.5gal of water in the 8-gal kettle to 160F. Warm the mash tun, check the water is still 160F.

3. Dump the grain into the mash tun,
4. Tip the 6.5gal of 160F water into the mash tun. Actually this starts out by moving it 1 quart at a time as I'm unable to safely dump the entire 6.5 gal of hot water in one shot anyway, and I heard it was better to add it slowly to the dry grain.
5. Stir with my giant 24" spoon to check no air pockets (just at the start)
6. Then leave for an hour. (temp remains constant for the hour within 150-155F - typically around 152F)
7. Recirculate until the flow of wort is relatively clear

8. Drain until empty back into the 8 gallon kettle - this typically yields about 4.2 gal.

9. Meanwhile I've heated the 2 gal kettle and 1/2 gal kettle to 170F

10. Dump 2.5gal of 170F water into the mash tun to sparge
11. Stir briefly
12. Wait 15 minutes
13. Recirculate until flow of wort is relatively clear

14. Add this to the kettle until the kettle is back up to the 6.5gal mark

15. Boil for an hour adding hops and Irish moss as prescribed

16. 45 minutes into the boil add the wort chiller to sanitize it (no water flow connected).
17. Transfer to the sink, connect the water flow to the chiller, also add blocks of ice into the sink
18. Stir the wort with the chiller and drop the temperature down to 70-75F
19. Siphon to 6.5 gal better bottle
20. Test OG - this is usually done with the final, rather trubby, bit of the wort.
21. Pitch yeast
22. Wait until airlock starts to bubble, then chill to prescribed fermentation temp in a temp controlled modified-freezer.

My recipe involved 11 lbs of grain for a pilsner, with an expected OG of 1.049 mine measured 1.044, so a little lower than expected. My previous brew called for an expected OG of 1.062 but my process only yielded 1.051 so lower still.

I'm wondering - are my OG's lower because I'm using a higher volume (6.5gal for the boil) than a typical recipe expects?

Specifically, with a 5gal recipe - what exactly is supposed to be 5gal? The pre boil volume, the post boil including trub volume, the volume initially put into the fermenter without the trub, or the bottled volume? I've been trying to target 5gals into the bottles, my last round yielded 4.66gal. But perhaps this is my misunderstanding and might completely explain my OG delta?

MANY thanks for reading this long one!

Roland.

Answer 1

Change that batch sparge to a fly sparge if you can. Use a good false bottom with little dead space (something like this works great: http://morebeer.com/products/stainless-steel-false-bottom-12-diameter.html). Also remember that the sparge needs even, unidirectional flow to get the sugars away from the grain. Never stir it if you don't absolutely have to. By stirring you're pushing sugarless, slightly tannic water from the top of the grain bed closer to the drain, making the wort weaker and more bitter.

Answer 2

I, too, was always coming up a few points short on my OG. My epiphany was an article in BYO magazine (I think) that explained the need to adjust recipes for one's own equipment and efficiency. My experience lead me to believe that recipes generally use a 72-75% efficiency value, which could explain why those are the defaults in brewing software.

I scaled my recipes using a 68% efficiency and now I almost always hit my target OG, without any equipment changes! It just costs me a little more base malt, but that's all.

I'll enter a recipe into brew software like Beersmith, Brew Toad or Brew Target (free). I'll set the efficiency at 75% and then add all of the ingredients in the recipe. I'll adjust the efficiency slightly until it matches the recipe's OG (usually 72-75%). This represents the "originally published" recipe.

Next, I'll change the efficiency to 68% (for my equipment) and adjust the malts (usually only the base) until I match the original OG of the recipe. Most software has an option to automatically scale the ingredients when you make efficiency or volume changes.

Published recipes make assumptions and should only be used as a base. Every brewer would need to make tweaks to account for his/her own process, equipment, efficiency, etc. I'm a novice brewer that switched to all-grain after my first batch. My first two all-grains were disaster-ish: drinkable but very disappointing. So now I just throw a little more grain into it. A pro brewer with crazy efficiency would probably use less grain than what most recipes state.

Answer 3

First, when a recipe says 5 gallons that generally refers to post-boil volume into the fermenter. This is how kits do it and I think public recipes in like BYO or zymurgy follow the convention.

That said, I'm curious about your numbers. Could you give more detail about the recipe you were brewing for those example volumes? Is this for the mentioned 11 pounds of grain, because if it is you're using far too much mash water.

Pardon me if this is a different recipe and you know this already...Your target should be 1.3-1.5 quarts of water per pound of grain. Numbers vary a lot online, but you should expect grain to absorb ~.5 quarts per pound of grain. If your mash is too runny it won't convert as well as you want it to, which might be responsible for your low gravity. If it seems like your grain isn't absorbing as much as it should, you might still have some dough balls in your mash that aren't getting wet. I add grain to my water so that I can stir constantly with something slotted, seems to get me less dough issues.

But double check that math, also it might be helpful to check your post-boil volume as well as your pre-boil, I don't see that in your writeup. Also marking your kettle and measuring your boil-off per hour would be useful in tweaking your pre-boil target volume to make sure you get as much wort out as you want.