Wednesday, October 03, 2007

Brew day - F5 Altbier (take two)

So this is my first post in a while. It's not that I haven't brewed in the last couple months, it's just that I've been brewing for parties. That means quick, tried-and-true mini-mash recipes which are fairly routine and not worth blogging about unless something goes drastically wrong. Thankfully, nothing did.

Anyway, after the last Altbier fiasco (see the last two posts), I decided to give the Altbier another shot this past Sunday. I also decided to just go with a 5-gallon batch this time, to eliminate some issues from the last time (mainly cooling, as it was 80°+ on the brew day). Unfortunately, it was another day with several issues (why can't my all-grain brew days go as smoothly as my partial-mash ones???), but we'll see how it all ends up. For now, here's a recap...

I mashed in at 168°F with a target temp of 152°F. Yeah, I know that's high, but my tun (a converted Rubbermaid cooler) doesn't seem to retain heat very well, so I'm more concerned about being too low than too high. One frustrating thing is, with the Gott-style coolers (that is, the cylindrical ones), I would think you would have a significant vertical temperature profile within the tun, so I don't think taking a temperature reading at the top of the tun is going to give you a good idea of the mash temp at the end of the mash. As such, I have no idea where my mash is finishing. I suppose I could stir the mash during the rest, as it will settle while recirculating, but for some reason that didn't occur to me until now. Mental note for next brew day. Anyway, I mashed for an hour and then recirculated for about fifteen minutes. It cleared up pretty quickly. I then sparged with 168°F water for about 45 minutes. Everything seemed to go well until I ran out of sparge water and I only had about four gallons of wort. I tried tipping the mash tun slightly but that didn't do anything. I decided to roll with it, figuring I had already extracted most of the sugars and could always add some water to bring the volume up.

As the wort was heating up, I took a gravity measurement. 1020 without the temperature correction; 1032 with a temperature correction, which estimated at a 1042 original gravity after accounting for evaporation during the boil. Dammit, I was pissed. How could my gravity be that low AND my yield be so low? Well, I figured I would again roll with it, rather than add some dry malt extract to bring the gravity up. I added my initial hops (Northern Brewer with a little bit of Spalt for logistical reasons) at the beginning of the boil, adjusting for a 3.5 gallon batch (since the recipe was obviously for five gallons). At fifteen minutes I added my immersion chiller and Irish moss. Then, when I was about ready to add the final hops, I realized I forgot the addition at 15 minutes. So I added half of what was left of my Spalt bag (roughly .3 oz), let it boil for ten more minutes, and added the final .3 oz at knock-out.

I chilled to around 70°F, racked to a carboy (with an estimated yield of--yikes--three gallons) and took a final gravity reading. 1052, only two points off from my target gravity. Of course, if you get that extraction for a 5-gallon yield, your gravity would be 1032. But at the same time, it's way better than the 1032 I estimated for 3.5 gallons. I attribute this error to a combination of two things: 1.) the inaccuracy of taking a gravity reading at 135°F, and 2.) while some have told me otherwise, I believe that the denser wort settles to the bottom of the brew kettle, so even though I stirred it well before taking my sample, my sample was drawn from the top which had a lower gravity (being a late running). Next time I'm thinking I should take gravity readings during the run-off to get a better idea of my runnings. Plus, had I done so this time, I could at least estimated what my yield would have been had I not run out of sparge water. (For the record, when I dumped out the grains, there didn't seem to be an excess of water so I suspect somehow measured my sparge water incorrectly).

Just for fun, I'm going to do some back-of-the-envelope calculation of what my gravity would have been had I not run out of sparge water. Let's start by assuming that gravity decreases linearly (which it obviously doesn't, due to the law of diminishing returns). Next, since my gravity reading after the sparge was 1032, and I had done some mixing, let's estimate the gravity of that final run-off was 1020. Now I've heard that it's supposedly not worth sparging below a gravity of around 1006, so let's assume that's what the gravity would have been at the end of the sparge. Since the average of 1020 and 1006 is 1013, we'll assume that would be the gravity of the final 2.5 gallons we should've extracted. That's approx. 33 additional gravity points we would have gotten. That gives us a final gravity of 1043 for a five-gallon batch. That would be 62% brewhouse efficiency, which still isn't great. Of course, there are a lot of faulty assumptions there, so who knows what it really would have been. Regardless, I'm concerned about my efficiency. I currently don't use a sparge arm; I'm thinking of making one and seeing if that helps.

Anyway, once I pitched the carboy went straight into the fermenter set at 65°F. Last time I fermented way too hot and bad things happened (especially since I'm using the White Labs Alt/Kölsch yeast, which doesn't like high temperatures). Of course, since I didn't make a starter, the cooler temp meant we didn't get fermentation until around 60 hours after pitching. I hope that doesn't cause any problems, though I guess time will tell.

Oh, and one other thing went wrong. When I was putting stuff away, I found an extra bag of Spalt hops. That's when I realized that it wasn't just the one remaining bag of hops that was supposed to go into the kettle; there was a whole 'nother bag as well. Fortunately, I'd rather add too little flavor/aroma hops than bittering hops, and if it needs more aroma I can always dry-hop (which will also give an illusion of more flavor). But we'll cross that bridge when we get there. In the meantime, I'm just glad that we have fermentation and we'll see what happens from here on out. Cross your fingers!



Blogger Ted Danyluk said...

Hi Russ,

It was really great to talk with you at the HOPS Oktoberfest. It was such a nice event. I really enjoyed most of the beers, the food was great, and a lot of people knew a lot of stuff about brewing and mead making.

After reading this post, I felt a little fatigued. I know when things go wrong at different stages, my emotions build up stress levels, and aid to an overall feeling of fatigue in the end.

Stirring the mash will do two things. It will help to distribute the temperature within the tun, and it will get the settling grains back into suspension. Grain suspension is very important and results in a better efficiency because more sugars can dissolve into all the surrounding water.

Also wondering if you considered batch sparging. I am finding it to be much easier with a little better efficiency that fly. Definitely worth trying out.

Hope it turns out good in the end. Lets swap beers some time.

4:43 PM, October 04, 2007  
Blogger Bill said...


Only tangentially related -- I saw a post of yours on BA about wondering if there were any US-brewed sticke alts. Long Trail in VT does a sticke -- Long Trail Ale is an alt, Long Trail Double Bag is a sticke alt. And truly wonderful, by the way.

Best wishes with the homebrewed versions.

Bill Farr

4:07 PM, October 09, 2007  
Blogger Adam said...

I think we've all had days like that. Heck I'm not even all grain brewing and I've had extract brew days that go that way.

Good luck and thanks for posting this unedited and very frank account of a brew day. I think it helps others steer clear of mistakes and also lends credibility to your blog :-)

8:40 AM, October 10, 2007  

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