Technological process of a Tuscany geothermical hemp beer
Matteo Iannone¹, Giacomo Carmazzi², Chiara Volpi³, Andrea Marianelli¹
1 La Staffetta Association
2 Carmazzi Farm
3 Vapori di Birra Brewery
First, this experimental test was reproduced once adding to the recipe both hemp and hops
(characterizing sample) and another, adding just hops (control or white sample). There are a lot of varieties of techniques for making beers. The best technique, that better suits a brewing style like American Pale Ale (APA) is the “ALL-GRAIN” technique. This technique, literally, consists in different steps of production of craft beer, which is based on the use, in fact, of malt grains and not the jar of concentrated malt extract. Hempitaly was made in the geothermal EGP (Enel Green Power) complex of Larderello. This is famous all over the world for its numerous high-sustainability systems able to use geothermal steam, coming from underground water sources, to produce electrical and thermal energy;
The most innovative aspect of this geothermal system is the fact that the developed energy is not only used for production, but also in sanitization processes. At present only refrigeration mechanisms do not provide for the exploitation of steam because they are based on extremely expensive systems. In any case, the use of geothermal energy allows, on the one hand, a reduction in costs in terms of electrical energy that can be quantified in a percentage of about 20% and, on the other, an improvement in the technological process with the achievement of process temperatures in much faster times.
Materials and Methods
2.1 The materials used in this technique are as follows:
Vessel for mashing/boiling (1000 L)
Vessel for sparging (1000 L)
Whirlpool (1000 L)
Mill for grinding malt
Fermenter (1500 L; glycol-cooling)
Thermometer (for food used with gradation up to or at least 90° C)
Density-meter (expressed by ° Brix, ° BABO, ° Plato)
Iodine tincture citric acid (pKa= 3.1-4.8-6.4 at 25°C)
Plate-heat exchanger water/glycol-cooling system
Geothermal System of the “Vapori di Birra” brewery near Sasso Pisano (PI)
2.2 Description of production process in “ALL-GRAIN” style.
The phases of production of beer with the “ALL-GRAIN” method are the following: (1) Grinding of malt grains, (2) Mashing, (3) Filtering and sparging, (4) Boiling and hopping, (6) Whirlpool, (7) Mash cooling, (8) Primary Fermentation, (9) Bottling and priming. Now they will be dealt with in detail giving, as much as possible, precise indications:
Figure 1. Typical scheme of prodution process in “ALL-GRAIN” style (Brewer’s Friend 2013).
Grinding of malt grains → using a mill we proceed to the grinding of malt grains. It is necessary to pay attention to the granulometry of the flour that will be made, which is not too fine. The grinding must only break the grain, do not crush it or crush it. The excessive fineness in the grinding can create problems during the filtering phase since the glumette will be able to create a sort of filter. Furthermore, if overly fine, the clarity of the finished beer can be damaged. If too much flour is suspended in the mash, the grains can be moistened before grinding, dipping them in water or spraying them. The diameter of grounded grains must be not too much finely causing “chill haze”. This is caused by proteins and tannins (primarily, contained in malt) suspended in beer. Haze particles don’t form because of the warm temperature. Therefore, the beer are chilled proteins and tannins react to create high molecular weighted macromolecules big enough to reflect light. In a present study by Cejnar et al., 2017, the turbidity or “haze” was caused by the interaction between proteins and polyphenols. One of the main cheap method is to boil the beer at high temperatures and, then cool as fast as possible.
In the recipe of the grist for the formulation of the Hempitaly® product they have been used for the basic malts 88% of Pilsner base malt and 6% Vienna base malt. Secondly, they have been used a small part of malt characterizing as 3% Weizen malt for sourish profile and 3% Carapils malt for more body (Table 1).
* Malt Weizen is used for his sourish profile and Malt Carapils to give more body to the product
Figure 2. Type of malt used in experimental test (top left Pilsner, top right Carapils, bottom left Weizen, bottom right Vienna).
Mashing → The grains have been crushed and the mashing phase is carried out in which the ground malt is left for about 2-3 hours infusion, following certain temperature steps or stops. This process has the purpose of extracting sugars and starches from the wheat, in such a way as to create a sugary liquid, the mash. The latter will be the fuel for the transformation of complex sugars to ethanol, mediated by yeasts. The mashing consists in turn of different phases characterized by different temperatures and durations, which are also called stops. These stops are useful to determine that the enzymatic reactions for the breakdown of starches and complex sugars occur correctly. Simultaneously with grinding, the water is placed on the fire and brought to a temperature desired for the first step (Chart 1). This is because following the addition of ground malt there will be a lowering of the temperature. The best ratio for this recipe is grain:water 1:3. Once the ground malt has been added, the pH value of the mash is measured, which must be between 5.2-5.7. In this recipe the mashing has be done in multi-step system. The mashing is concluded with the mash out or 5 minutes at 78 °C which have the purpose to definitively block the enzymatic reactions and fluidize the mash for filtration.
Figure 3 a. Left side shows the temperatures, in function of time, for the mashing programs MP-1, MP-2, MP-3 to be characterized as sugar production. MP-1 and MP-2 are the programs used for homebrewing. MP-3 is used for industrial brewing. The temperature is responsible for solubilization and activation of the enzymes, that cleave the molecules, as shown schematically to the right (De almeida et., al 2018).
As you can see from the upper figure the initial concentrations shown that the same concentrations were obtained for glucose and fructose. However, maltose and dextrin presented different values. Firstly, comparing MP-1 and MP-2, in relation to the final concentrations, MP-2 produced lower values for maltose and dextrin, compared to MP-1 (Figure 3 a). The main reason was that in MP-1, a step at 45 °C was used for gelatinization of the starch. At this temperature, there was also the activation of α-glycosidase, which breaks down starch to maltose and dextrin, among other sugars. However, a temperature of 50 °C was used in MP-2, which activated β-amylase, but the starch was still in the solubilization phase, so there were fewer bonds available to be broken by the enzyme. In MP-1, the activation of β-amylase only occurred in the 55 °C step, when there was enough solubilized starch present for more effective action.
In particular, the upperside table shows time and temperature for each phase in the Mash-in process. At first, in the mashing process for the product, called Hempitaly®, the wort was brought to the right temperature (45°C).
After that, we proceeded in according to the following scheme (Chart 1):
45°C for 10 minutes (protease enzymes react to hydrolize low-weight protein as nourishment for yeast)
50°C for 20 minutes (amililithic activity)
62°C for 20 minutes (β-amylase activity, pH 5.0-5.5, maximum activity)
65°C for 20 minutes (β-amylase activity, pH 5.0-5.5, enzymatic synergy point between amylases)
70°C for 20 minutes (α-amylase activity, pH 5.6-5.8, maximum activity
78°C for 5 minutes (enzymatical inactivation phase)
Filtering or sparging Now the liquid phase must be separated from the grains, that is the residues of malt through a filtering process. Initially, it is appropriate to let the mash decant, that is to separate the coarse particles from the lighter ones using the gravity force for about 15 minutes in order to further reduce the suspended flour particles. For filtering it will be appropriate to use a way to get a passage ONLY the mash, but not the grains. The mash flows through the holes while the threshers remain blocked. The thresh will also allow a natural filtering of the mash even more efficient. With a garden watering can we start with the addition of water without the disgregation of the bed of threshers and then, collect in a container in a sanitized fermenter. This process must be repeated six times adding in total 780 L. Moreover, the pH of water would be better not higher than 6. Afterthat, we can boil the wort for 60’ and collect the values about carbohydrates content expressed as degree Plato (°P):
Boiling → 12.5 °P
During → 11.4 °P
End boiling → 12.6 °P
The definition for degree Plato is the density of a solution measured in degrees Plato as th equivalent of the density, measured in W/W percentage of a solution of saccharose diluted in water. We continue to see the mash until it will come out clear. It is a process that usually takes two or 3 hours. In this phase the “mash hemping” technique was used adding hemp at the beginning of the rinsing of the threshers, directly on them. This technique was used to increase the aromatic profile of hemp. It is important that the mash come down slowly, as it could remove the bed of threshers and clog the filter.
Boiling and hopping → When the filtering phase is finished, beer must be boiled, and which usually takes 1 hour. This phase is very important for sterilizing mash, clarify mash and fix the bitterness and the flavor. During boiling process, the hops are added in the times and in the doses provided by the recipe. The hopping is subdivided into bitter or aroma hops. The bitter hopping has a longer life and serves to give the beer bitterness. The aroma hopping lasts between 10-15 minutes and serves to transfer scent and aroma. From the point of view of the IBU (international bitterness units) it is necessary to calculate it based on the content of alpha acids (AA%), which is specified on the packaging of hops. This molecule has an anti-tumoral effect very strong. Depending on the style and recipe, a range of IBU values it will be provided. In the case of the American Pale Ale style the value of IBU will have to be between 35-45. The fresh hemp was added at the end of boiling (10′ at time Ø) gives the finished product an aromatic profile characteristic of fresh hemp, due to monoterpenes such as α-β-Pinene, α-β-Mircene and β-Ocimene. These give herbaceous-resinous and fruity-woody profiles. In the case in which they were provided by the recipe, at the end of boiling, 5-10 minutes before the end of this phase (Chart 2). After boiling, whirlpool is usually done. This procedure consists in centrifuging the mash to collect suspended substances such as proteins, hops residues, etc. in the center of the pot.
Mash cooling → mash be brought to a temperature between 20 and 22 ° C using any cooling technique and this must take place as quickly as possible. There are multiple ways to cool the mash. The best is cooling by plate-heat exchanger, where the hot mash and the coolant (tap water) circulate in the opposite direction. The two flows come into contact only by direct contact between plates, but never mixing. The heat of the mash is exchanged with that of the coolant by lowering the temperature. Otherwise, if is not in possession of a plate-heat exchanger is possible to immerse the pot in a tub of cold water by checking the temperature drop with the thermometer. The temperature drop will be quick initially then it will be very slow, and you will need to be careful right now. Before inoculating, take a sample of mash and measure the density with a densimeter or with a Brix scale refractometer. At the end of the fermentation, we will have to measure the density again and must have a value about ¼ lower than the initial density (OG). This value will be useful to monitor fermentation and to know the alcohol content of beer. It will be enough to subtract the initial density from the final one and divide the result by 7.45, after which it will be necessary to multiply by 100 and express the result as a percentage. Once this is done, the mash is oxygenated to favor the start of the fermentation, stirring for at least a couple of minutes. Finally, we inoculate the yeast and mix again. Then, we close the fermenter by closing the hole in the lid with a bubbler.
Primary fermentation → Primary fermentation lasted for 12 days at 20 ° C. It was using a neutral yeast from the Fermentis US-05. Then the beer was attenuated with an OG equal to 12-14 and proceeded with gradual lowering of temperature up to 4 °C. This trick will be necessary to facilitate the nucleation of carbon dioxide and reduce the diameter of the bubbles of gas, which after the priming could cause problems related to the frizziness of beer. Finally, the beer that does not mature enough, was kept for about 1 week in a thermostated warehouse at a temperature equal to or lower than 18 °C before bottling.
Finally, after 7-14 days, take small samples of beer to check the density and verify that the fermentation process is finished. If the mash has high density levels it is possible that there are still high concentrations of fermentable sugars and that the fermentation has not yet completed its course. If, on the other hand, the density remains stable for several days, it means that the time has come to bottle.
Bottling and priming→Priming means the addition of sugar, which will be necessary to give further nourishment to the yeasts and allow them to form compounds that are pleasant and necessary for the final maturation of our product. In addition, the dose of sugar to be added will be closely linked to the type of beer to be made and the size of the bottle. After bottling and carbonate, you do not have to store the bottles in a place at a constant temperature between 22-25 °C, protected from the sun, for about 20 days. Once 20 days, the nucleation of carbon dioxide can be repeated by placing the bottles in the refrigerator at 4 ° C for 4-5 days. we have put them in a thermostated warehouse at temperatures below 20 °C.
The cold will allow you to refine the beer by attenuating the strongest smells of fermentation and to deposit any suspensions making the beer clearer.
Figure 4. Comparison of the aromatic profile between hempitaly and a commercial hemp beer. (Flamini, Ascrizzi, Cinque – Cannabis sativa L: Caratterizzazione fitochimica di tre Cultivar da Fibra a basso o nullo contenuto in Δ-9-THC e loro utilizzo per l’aromatizzazione della birra)
1. monoterpenes hydrocarbons
2. oxygenated monoterpenes
3. sesquiterpenes hydrocarbons
4. oxygenated sesquiterpenes
5. no terpenes