[hulkavitch]

I am planning a bavarian weizen for this weekend. In the Jamil Z. podcast on bavarian weizens he brushed over doing a step mash at 50-60-70 celsius. Any one had any experience with this? Should i just do a single infusion at 152? If i were to step how long of a rest per step?

Thanks

[nateo]

Single infusion is fine. I like 149* but 152* is basically the same.

[jmcamerlengo]

Single Infusion will work fine, however I really like employing a ferulic acid rest. 111F for 20 minutes does the trick. From there I usually go to 131 for 10 minutes and then 149 for 30 minutes and 158 for 20 minutes then mashing out at 168 for 10 mintues. However I do this because I direct fire and its easy for me and I like the results.

If you dont direct fire a good regimen may be 111F for 20 minutes then 152 for 60 minutes.

[hulkavitch]

Jason,

The 20 min rest at 111 sounds like soething i could do. What water volumes do i use for probably 11 lbs of grains?

[jmcamerlengo]

Jason,

The 20 min rest at 111 sounds like soething i could do. What water volumes do i use for probably 11 lbs of grains?

Im assuming you will be adding boiling water to get from 111 to 152?

If thats the case, thats a big temp jump to achieve with boiling water so I would start pretty thick on the initial mash in.

For 11 lbs of grain I would use a 1 lb to 1 qt ratio to start with, so 11 quarts total. Then hit it with boiling water to achieve a final mash ratio of 1.5 qts/lb - 2qts/lb.

Its really going to be dependent on your system and how much water it can hold. Mash thickness isn't too much of an issue, I just wouldnt get to far above 2 qts/lb as a final ratio.

You can start at .85 or .9 qts per pound and finish more in the 1.3-1.7 qts/lb range if your system is smaller and cant handle the water volumes.

[hulkavitch]

Thanks for the input. First time step mashing.

[gordonstrong]

How long for rests?  Generally 10-15 min for the lower temp rests and at least 30 for your main saccharification rest.  If you do multiple sacc rests, go longer on the one that favors the wort fermentability you want (lower temps = more fermentable).  Higher temp sacc rests take longer than lower, so they should be longer if you want them to do something meaningful.

You can step by infusing boiling water, direct firing the mash tun, or decocting.  Depends on your system and goals.  Infusing is easiest, but you should start thick.  Direct firing is what I use most often, but I can recirc my mash tun with a pump.  I'd worry about the temp being radically different at different layers of the mash without that approach.  Decocting is a step mash, and is good if you have the equipment and time.  It gives other flavors, darkens the wort, but doesn't really change your overall mash thickness, if that's a concern (capacity and such).

[morticaixavier]

How long for rests?  Generally 10-15 min for the lower temp rests and at least 30 for your main saccharification rest.  If you do multiple sacc rests, go longer on the one that favors the wort fermentability you want (lower temps = more fermentable).  Higher temp sacc rests take longer than lower[...]

Gordon, is this true of step mashes only? I always thought that higher temp sacc rests went quicker. I usually do a 158* for 45 minutes but a 148 at 90+. am I doing it wrong? That's what beersmith tells me to do. (i'm not a robot, I just follow directions exactly  )

[gordonstrong]

No, it's true in general.  Briggs, Brewing Science and Practice, has a nice graph on p.87.

According to Kunze, the fastest activity for mash conversion happens in the 62-64C (144-147F) range.

Basically, higher temperatures tend to cause enzymes to start out faster but they peak at a lower rate because they start to be denatured at the higher temperatures.  So they wind up taking longer.  It's in the shape of the curve of enzyme activity over time.  I guess it also depends on the concentration of the enzymes in relation to the amount of starch present.  If enzymes can convert everything during their rapid boost phase, then you don't have to worry about the longer limit phase.

But I wouldn't just focus on this one fact to the exclusion of other things.  It's easy to take what I said and then misapply it.  So you ferment at 144 because you want a fast, complete mash.  But what's that do to your wort composition?  Is that the mix of sugars you want for the beer you're making?  Maybe.  Maybe not.  You don't know if you don't think about those other things.

Science is nice for understanding what's happening, but it's really easy to draw wrong conclusions and misapply it.  Stick with the advice in my previous post and use this to understand the background.

[nateo]

But what's that do to your wort composition?  Is that the mix of sugars you want for the beer you're making?  Maybe.  Maybe not.  You don't know if you don't think about those other things.

Wort composition is something I don't think a lot of homebrewers consciously consider. I've been reading a lot about ester formation recently, and it's interesting to see how the flavor profile of the beer is influenced by the wort composition. Brewing a Dampfbier (100% barley grist w/weizen yeast) can be very educational.

[malzig]

The temperature optimum will depend on the enzyme you're considering, as well as availability of substrate (starch) which is often limiting in saccharafication.  ß-amylase has an optimum at 140°F (considering conversion and denaturation rates) while α-amylase has an optimum at 158°F.  The combined optimum for fermentable extract seems to work out to be about 149°F, in practice, though researchers have found optimal extract at temperatures as high as 155-158°F for single infusion mashes.

One reason for this relates to the temperature required for complete gelatinization.  It can be very difficult to ever get complete gelatinization in the mid-140s, though this can be aided by some temperature schedules that can reduce the size of starch granules.  Since the rate of starch gelatinization often becomes limiting before enzyme denaturation does, lower temperatures can easily result in a slower practical conversion at lower temperatures.

It's a very complicated system and it is very difficult to summarize all the data to come up with a single ideal value, but I find that the more casual observations I've made in my brewery tends to agree with the data that shows higher temperatures result in faster, more complete conversion.

No, it's true in general.  Briggs, Brewing Science and Practice, has a nice graph on p.87.

According to Kunze, the fastest activity for mash conversion happens in the 62-64C (144-147F) range.

Basically, higher temperatures tend to cause enzymes to start out faster but they peak at a lower rate because they start to be denatured at the higher temperatures.  So they wind up taking longer.

The graph on page 87 in Briggs, et al (2004) is an idealized graph of the effect of temperature on combined activity and denaturation.  It might be more telling to look at Figure 4.9 on page 107 that shows the highest level of measured extract to be at ~66.7°C-70°C (or 152°F-158°F), no matter how long the mash continues.