Topping up technique. Good/Bad?

During my last AG session, I decided to save about 1/2 gallon of runoff from my mash after I filled my boil kettle with 6.25 gal. Post boil, I used that runoff along with some ice to top the wort up to 5.25 gal. I figured that if it was added at flameout it'd dilute the final product less than water and add a few more fermentables as a bonus.

Other than not getting exact predictable results, can anyone see a down side to this? It seemed like a good idea, but that's gotten me in trouble before.

Since I collected the wort one day and boiled 2 days later, I also collected a little of the runoff to use for a starter. It worked great, although I would recommend refrigerating the sweet liquid if it sits for more than a day. It's a good way to save on buying DME.

Well....you don't want to be adding anything to your wort post boil which hasn't been boiled...especially leftover runoff. Not a good idea....good luck though.

Eek....unboiled wort could have a lot of pretty nasty stuff.....not sure which of it can survive the 150-160F temps for an hour though....good luck, I sure as hell would never have risked it!

Edit: Dear god, you waited 2 days after collecting the wort before you boiled most and topped up with the rest? You sir, are a brave man.

Yeah, in retrospect prly not a grat idea. However, if it's refrigerated it'll stay sanitary before the boil, right? I know that a late addition LME at flameout will pasteurize the malt enough (so I was told)......why not the same with the unboiled wort? I know the boil is a valuable conversion process, but if the heat sanitizes the late addition, what harm will it do? Are the sugars fermentable? I figure they are. I just though it'd be a good substitute for water.....

guinnessface said:

Yeah, in retrospect prly not a grat idea. However, if it's refrigerated it'll stay sanitary before the boil, right? I know that a late addition LME at flameout will pasteurize the malt enough (so I was told)......why not the same with the unboiled wort? I know the boil is a valuable conversion process, but if the heat sanitizes the late addition, what harm will it do? Are the sugars fermentable? I figure they are. I just though it'd be a good substitute for water.....

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Oh the sugars are fully fermentable...it's just that 155*F wort isn't sanitary....flameout is at 212*F, which is a pretty big difference. Your wort is sanitized by boiling....if you don't boil, it isn't sanitary, (hell, 140*F is primetime bacterial growth temp....the "danger zone" for cooking, where bacteria multiplies like crazy, is 60-140*F).

I could be very wrong....I've never tried it, so maybe it's me that's crazy...but honestly, if you are worried about "diluting" your wort with top up water, either sparge more before the boil, (but I'm guessing 6.25 gallons is an equipment limitation?), or just add an extra lb or three of grain to the mash so that you dilute down to your desired OG.

I transfer the extra draining into a 1.5 gallon electric kettle, that I co-opted/stole from the kitchen, bring it to a boil, cover and simmer while the main boil is in progress. If I need extra wort after the main boil is transferred to the fermentor I use the boiled runnings from the electric kettle.

geezerpk said:

I transfer the extra draining into a 1.5 gallon electric kettle, that I co-opted/stole from the kitchen, bring it to a boil, cover and simmer while the main boil is in progress. If I need extra wort after the main boil is transferred to the fermentor I use the boiled runnings from the electric kettle.

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This would work much better than what the OP did. Another option is to just pull aside some of your runoff and add it to the pot as you boil off the liquid that's in there. Saving some of the wort directly from the mash tun is done sometimes to intentionally sour a beer due to the bacteria that remain alive through the mash.

Hopefully you like sours, as it could turn out really good still. It's probably going to take a while (months to a year or so) to come into its own. Make sure you give your fermenter a very thorough cleaning and sanitizing after the batch is done. If it's a plastic bucket you may want to just set it aside for doing sour batches if you like them so you don't unintentionally infect future batches.

stageseven said:

Another option is to just pull aside some of your runoff and add it to the pot as you boil off the liquid that's in there.

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That's what I do. I do BIAB and its much easier to squeeze the bag once it cools off a little. I try to add back any liquid that boils off to the boil slowly so it doesn't stop boiling. If my preboil gravity is high I will sometimes add water.

stageseven said:

Hopefully you like sours, as it could turn out really good still. It's probably going to take a while (months to a year or so) to come into its own. Make sure you give your fermenter a very thorough cleaning and sanitizing after the batch is done. If it's a plastic bucket you may want to just set it aside for doing sour batches if you like them so you don't unintentionally infect future batches.

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What he said. You have an infection now, almost certainly. It may be a good one though, if you are patient enough to wait.

Bad idea:

1. none of that wort was boiled to drive off DMS. cooked veggies anyone?
2. none of that wort was boiled to kill the bad stuff that always lives on grain. You're not even supposed to mill the grain where you brew because of the huge increase in risk for lacto infection. 160F does not kill lacto, so you very possibly poured a lacto culture into the wort
3. fridge temps keep nothing sanitary, and what you had wasn't even sanitary to start with. It probably did prevent the lacto colony from going bonkers...but to what end?

the beer might be ok...but this will be an interesting one to watch develop.

There I go improvising again....... I thnk there's enough evidence here to support the fact that I had a terrible idea. I have the "quarantined" substance in a 7.5 conical right now. It's an imperial red, so maybe the higher abv will ward off some of the side circus. I'm also hoping that since I added it right before flameout, the 212 deg temps killed some of the bad stuff. It's been in there for about 3.5 weeks, and the samples lead me to believe it'll be drinkable, however, I was planning to let this sit for a while anyway.
I appreciate the candid feedback as well as the technique of doing a side-boil. I'll stick to the script next time...thanks again

hrm...for some reason I originally thought you were adding this as top up after it has cooled...come to think of it, adding it at or just before flameout might be just fine. I mean, not the best example of a perfect practice, but should be easy to get lucky with it.

If it doesn't taste like ass after 3.5 weeks, you're most likely fine. I retract my earlier pessimism.

I'd still do a side-boil in the future though.

Update: The beer is definitely drinkable, but sure enough, pretty sour up front. I'll hold onto it and see if it mellows with age. Not a total loss.

guinnessface said:

Update: The beer is definitely drinkable, but sure enough, pretty sour up front. I'll hold onto it and see if it mellows with age. Not a total loss.

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Unless you're storing it cold, it will likely get more sour with age.

Good point. I was hoping it would mellow a bit. This may be a batch reserved for the back of the fridge, if not the drain. Although, its amazing how the taste improves after a few beers ahead of time........

dumped it. sad face

Sorry to hear about your loss, but I would have kept it and let it sour more. I never caught if this was an equipment thing and you needed to top off to get to a larger volume? If so, I would do as others recommended and add the extra back with enough time to boil off DMS, create break, and sanitize.

Another option, which I use as standard brewing practice, is high gravity brewing technique. The best thing about this is you can cut post-boil, going into your fermentor, or save on fermentor volume and cut post-fermentation like the big boys do. Every step is different, and I prefer to cut post-boil to help chill faster. All it takes is proper planning (adjustments to hops and gravity in your kettle) and sanitation (pre-boiling your cutting water) and you can max out your equipment for more beer. I don't like to cut with more water than 40% and also with beers heavier than 1.064, but under those amounts I am very happy with my results. Lighter beer styles work best, but I even do this on my house APA with zero negative effects.