Dear Mr. Wizard,

I have two questions for you. One deals with late additions of malt and the other with “turbo conditioning” — I’ve been reading BYO recently and I’ve noticed that a lot of recipes are calling for the late addition of malt extract. Is there a benefit to this? I always thought that extract went in after the grains and before the boil, for more efficiency of the malt. My next question has to do with the fact that recently, I’ve been conditioning my newly bottled beer upstairs because it’s much too cold in the basement. I keep it next to the heater vent where the average temp is 72 ºF (22 ºC). My beer has been carbonated in about 3-4 days time, whereas in the summer it takes about 2 weeks in the basement. I know that good things come to those who wait, but am I doing my beer a disservice by this method of “turbo conditioning?”

Neil Herrick
via email

Mr. Wizard replies:

Like all techniques in brewing I suggest critically evaluating what is being done to brew beer. In the case of wort boiling the goal for all-grain brewers is to kill bacteria from malt, denature enzymes, precipitate proteins, adjust wort gravity, remove unwanted volatiles (such as DMS) and isomerize hop acids. The latter goal is actually hindered by high wort gravity.

Brewers who have small brew pots and are unable to boil the entire wort volume sometimes add dry and/or liquid malt extracts late in the boil. These partial-mash brewers boil the wort extracted from malt to do all the things that is required for wort boiling, then at the end of the boil add the remaining extract in liquid or dry form per their recipe. A short hold at high temperatures is sufficient to kill any bacteria these ingredients may carry since liquid and dry malt extracts have already been heat-treated during manufacture and do not have high bacterial loads. After the high-gravity wort has been cooled the gravity is adjusted with water.

The benefit to this method is that wort produced from grain is boiled at a normal gravity along with hops just like an all-grain, full wort volume brew and all of the requirements of boiling are met. Dry and liquid extracts do not need to be boiled because these ingredients were boiled when concentrated at the extract plant. Furthermore, boiling extracts has absolutely no affect on efficiency. So the simple answer is that this is a sound method and has no obscure pit-falls that may end up causing disappointment.

Your next question is about keeping your beer warm during conditioning. This is a real world problem for commercial breweries selling bottle-conditioned beers. As you point out, storing beer in the basement or an underground cellar reduces the air temperature to the average earth temperature of the location of the cellar. In most parts of the world the average earth temperature is about 55 ºF (13 ºC). This impairs the speed of bottle conditioning, and for many ale strains is really too cold to get much carbonation at all.

This is why bottle-conditioned beers are typically stored in warm cellars controlled to a comfortable temperature of about 75 ºF (22 ºC). This is plenty warm for the yeasties to do their work in a reasonable time frame and is not so warm that the beer starts to prematurely age because of high storage temperature. This practice is relatively common in Europe and the United States among brewers who bottle-condition their beers. Duvel in Belgium, Sierra Nevada in California and New Belgium in Colorado are three breweries I know who have warm cellars. I know that at Sierra Nevada beer is held for about a week before being released for sale.

So in the commercial world of brewing where time is money, warm conditioning reduces the number of cases that are sitting around waiting for carbonation to happen. Bean counters like to minimize this type of inventory and warm conditioning helps control inventory and the conditioning process. At home the economic drivers of inventory control are different, but why wait 2 weeks to sample your next tasty brew when you can cut down the time to 1 week? There is no reason whatsoever not to practice this method . . . I declare open season on “turbo-conditioning!”

Dear Mr. Wizard,

I have a question regarding the mash out. I use single infusion mashing with a modified picnic cooler. When attempting to mash out I use a good deal of near-boiling water just to raise the temperature from the mash to 170 ºF (77 ºC). Not having the ability to apply direct heat to the mash tun, I was wondering if I could, like in decoction mashing, remove the thick portion of the mash, boil it and return it to raise the temperature to mash out, thus not having to add additional water. Would this extract tannins and “grainy” flavors since the beer was made via the infusion method? If this is feasible how much would I pull off of the main mash to boil in order to achieve the mash out temperature?

Paul Kempkes
Buffalo, New York

Mr. Wizard replies:

The easiest way to go about solving this problem is to not mash out. Breweries who have infusion mash tuns have no way of doing a decoction and do not add a bunch of hot water to the mash to increase its temperature. Instead, infusion mash brewers usually start collecting wort and sparge with water that is around 168 ºF (76 ºC) and allow the temperature to slowly rise during wort collection. While mashing out does stop enzyme activity and “fixes” the carbohydrate profile of the wort, the main reason for mashing-out is to reduce wort viscosity and improve wort flow through the grain bed. This is more important when doing stirred, multi-temperature mashes because the mash bed becomes denser. Infusion mashes are usually easy to run-off and this is not so much of an issue.

You can do a single decoction to increase mash temperature if you really want to mash out. A little extra malty or grainy flavor is typically associated with beer made with decoction. How much mash to boil is a weighted average calculation. In this case you want 100% of the mash to be at 170ºF and have (100 - x)% at 155 ºF, for example, and (x)% at 212 ºF. The equation to solve is: (1) x (170 ºF) = [(1 – x) x 212 ºF] + [(x) x 155 ºF]. Solving this equation for x results in 0.74, meaning that 74% of the mash should be left in the mash tun and 26% of the mash should be boiled.

You probably will find that this will undershoot the desired temperature of 170 ºF (77 ºC) because some heat is lost when the two portions are mixed. This can be accounted for by deflating the decoction temperature used in the calculation based on empirical data. You can solve the equation in reverse to determine what temperature to use in the future. If the temperature only increased to 165 ºF (74 ºC), solving the equation (1) x (165 ºF) = [(0.26) x (y ºF)] + (0.74 x 155 ºF) indicates that 193 ºF (89 ºC) was the effective decoction temperature. Using this value for future brews suggests boiling 39% of the mash.

For the sake of simplicity, I have assumed that there is no difference in the thermal properties between the thin and thick mashes because there is no easy way to measure the mash thickness in the portion of the mash removed for boiling. I apologize to those readers who wish to consider every possible variable in brewing calculation and am sure those who wish to make my simple algebra more complex will figure a way to do so!

So there you have the answer to your question. If you really want my opinion — you are getting it whether you want it or not! — I suggest keeping things simple and only adding levels of complexity to your routine if you have a real requirement. If you have a problem getting the mash easily flowing through your mash tun or have a flavor-related concern that this will address I give the added complexity two thumbs up, otherwise keep it simple!