Monday, August 29, 2011

Brewing Improvements

Update: my oak beer still tastes like crap.

So my past few beers I've brewed haven't been the pinnacle of success. All brews came significantly under their OG.

A quick primer on OG and gravities. Measuring the specific gravity of a liquid tells you how thick or thin it is compared to water. Water being a 1. This is done with a hydrometer. OG stands for original gravity. OG is measured at the beginning of the fermentation process right when you dump the yeast in your fermentation vessel (bucket, carboy, bathtub, what-have-you). Ideally it measure how much sugar has been extracted from the grain and resides in your wort. This sugar is what gets eaten up by all the little yeasties to make alcohol. The counterpart to OG is FG. FG stands for final gravity. This is measured when your yeast is all done dining, and fermentation has slowed to a stop (essentially). The whole idea is that by subtracting your FG from your OG (and dividing by 0.75) you get alcohol content.

Now you see where my conundrum comes into play. If my beers' OG are coming in low, there's not enough sugar for the yeast to devour. Not enough yeast to devour means not enough yeast pooping alcohol. Which means my alcohol levels were way below style. This effects the flavor and body of the beer. It's like taking a shot of vodka that's 50/50 water. Ok, it's not that noticeable, but still not good. Talking with some of my brewer friends I've come up with 2 things I've been doing wrong that contribute to sugar extraction.All of which takes place during my sparging.

1 - Slooooow down hoss. 
So I know that sparging is to be done slowly. Lautering slow (60 to 90 minutes) is beneficial in a few ways. Slow flow prevents your grain bed from getting too compact, leading to a stuck sparge. Slow flow gives the chance for the grain to release more sugars. A slower flow will also give you a nice even sparge, and prevents channels from forming.

What I didn't realize is just how critical this could be. A friend of mine was listening to a podcast the other day about sparge times. Apparently the difference between sparging for 60 minutes and 90 minutes yielded an extra 10% efficiency bringing them up to around 80%! I didn't realize how much of a difference that could make. It then dawned on me that all my brews I ended up finishing the sparge around 5-10 minutes short. Knowing what I know now, I'll probably jack my time up to the 1:15 range to start and see what my efficiencies look like. My brew day is long enough as it is.

2 - Keep up that sparge temp!
 Here was my issue. Typically to sparge, I gravity feed my AutoSparge using the hot water from my hot liquor tank. The hot liquor tank (picture, right side) is just a keg with the top cut out of it. I use it for the mashing process as well. To gravity drain it I have to hoist it up on the table behind it? See a problem? I've got a keg, that's well over 170 degrees, with over 10 gallons of water in it. My rough estimate puts the weight over 100 lbs. Did I mention it was f%@#ing hot? I've almost killed myself a number of times. To combat the heat I would spray it off with my hose, drastically dropping my sparge temp. Keeping the sparge at the right temperature is critical, and quite frankly, I neglected it. Too cold, no sugars, too hot, lots of tannins. I realized I could put a valve on the output of my pump and throttle the flow down for my autosparge. Now I can keep my keg down, and monitor and adjust the temp as I see fit. Happy day.

We'll see if this helps! It damn well better. I've got some brewing to do in the next few weeks. There's the next company homebrew extravaganza. There's also a birthday coming up that requested a keg. No problem! I aim to please.

Any question on OG? Ask me anything!




3 comments:

  1. Are you taking your OG before pitching your yeast or after pitching?  From reading your blog here, it sounds like right after pitching but everything I have read elsewhere says to take it just before pitching. I'm just curious.  Still trying to learn as I go (like most everyone else I guess)

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  2. I take my OG after I pitch my yeast. I've heard the same thing as you have, but as long as you dont wait and take it immediately after pitching, that small of a fluid addition wont affect the density of the water.

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  3. (this might accidentally be a double reply) I take my OG after I pitch my yeast. I've heard the same thing as you have, but as long as you dont wait and take it immediately after pitching, that small of a fluid addition wont affect the density of the water.

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